Four answers, and three of them change the price
The tape is out and there are four places this unit can go. The integral garage, where the board already is. The utility room, which is two and a half metres of wall between a washing machine and a boiler. The roof space, which is empty, boarded, and the one the customer keeps pointing at. Or the outside face of the gable, which nobody has suggested yet because it looks like an admission of defeat. The quote that was emailed last week assumed the first of those, and it assumed six metres of cable.
None of this is aesthetics. The position sets three things that each carry a cost, and they are not the same three things a homeowner is thinking about. It sets what fire-resisting construction has to exist between the battery and the people asleep upstairs, which is either already there or is a day's work and a materials line nobody priced. It sets the cable run, and specifically which end of the system takes the long one, because a direct-current run and an alternating-current run tolerate distance very differently. And it sets the ambient temperature the equipment lives in, which is what the warranty and the capacity curve are both written against.
There is a fourth outcome and it needs saying out loud on the doorstep rather than in an email a fortnight later. Some houses have no compliant position. A mid-terrace with no garage, a kitchen that runs the full width, a roof space the guidance now argues against and a single external wall facing the pavement is a house where the honest survey answer is that the system as quoted does not have a home. Finding that out while the customer is standing next to you costs a survey visit. Finding it out after the equipment has landed costs considerably more, and it costs it in the one conversation nobody wants to have.
What each room is actually offering
Walk them in the order that eliminates fastest rather than the order they occur to the customer. Separation first, because it is the one that cannot be bought back with a longer cable. Then temperature, because it silently changes what the system delivers and what the manufacturer will honour. Then access and cable, which are money rather than obstacles.
The comparison below is about the room, not about the product. Every unit on the market brings its own permitted-location statement in its installation manual, and where that manual is more restrictive than the adopted code it is the manual that binds you, because installing outside it is installing outside the listing the whole approval rests on.
| Position | Ambient through the year | Separation position | What usually rules it out |
|---|---|---|---|
| Integral or attached garage | Cold and damp in winter, close to outdoor temperature; stable in summer | Often part-built already, because a garage attached to a dwelling is separated from it by requirement rather than by choice | The car. The clear working space in front of the equipment is not negotiable and a garage bay is narrower than people think |
| Utility room, plant cupboard or hall store | Warm and steady, the most favourable band the house offers | Rarely present, and if the cupboard is under the stairs it sits on the escape route, which is the worst place in the building | Volume, working space, and the boiler, cylinder and consumer unit already competing for the same wall |
| Roof space | The widest swing in the building: near outdoor temperature in January, far above the rooms below on a July afternoon | Current UK guidance for dwellings has moved firmly against it, and the residential code lists permitted locations rather than prohibited ones | Guidance, then access, then the fact that a trussed roof was never designed to carry a hundred kilograms at a point |
| Outside wall or detached store | Full outdoor range, so the enclosure rating and the low-temperature behaviour both have to be right | Simplest case, because the separation problem largely goes away with the shared wall | The unit not being rated for external mounting, exposure on a driving-rain elevation, and the run back to the board |
Separation is a question about the other side of the wall
The fire question on a domestic battery is not whether it will catch fire. It is what happens to the rest of the house in the hours after a cell in it goes into thermal runaway, and the answer is decided by what stands between the enclosure and the occupants, and by whether the route they leave through passes the battery. That is why an understairs cupboard is the position to argue hardest against: it is usually the only escape route from the first floor of a British house, and it is also, by a wide margin, the position customers suggest most often.
In the United Kingdom the specification to work to is PAS 63100, which was written for exactly this installation and sets out where in a dwelling a battery system may be placed and what fire-resisting construction has to separate it from habitable space and from escape routes. It is markedly less permissive about roof spaces than the practice that preceded it. The IET Code of Practice for Electrical Energy Storage Systems covers the wider installation, BS 7671 covers the electrical work including the prosumer's installation provisions in its Part 8, and where the position is an integral garage the separation between garage and dwelling is a building-regulations matter under Approved Document B rather than an electrical one. In North America the equivalents are NFPA 855, which has a chapter specific to one- and two-family dwellings, and the International Residential Code's stationary storage battery provisions, which answer by listing the locations a system may occupy. Read the current edition of whichever applies at the address, because all of them have moved.
Two things about those documents matter more than any number in them. The first is that they set both a separation requirement and a location list, and satisfying one does not satisfy the other — a beautifully lined cupboard in a bedroom is still a battery in a bedroom. The second is that where a standard permits a reduced separation, the permission usually rests on large-scale fire test data for that specific product, generated under UL 9540A, and that is manufacturer evidence rather than a code table. If a reduced separation is being relied on, the test report is a document you should be able to produce, not a claim from a datasheet bullet.
What all of that turns into on site is a lining. If the wall behind and beside the unit is not already fire-resisting construction, somebody is boarding and jointing it, and that is boards, fixings, tape, filler and a day. It is one of the two most commonly omitted lines on a battery quote, and the other is the working space in front of it.
What actually gets built into the wall
- Clear working space in front — not a component but a reserved volume, and the part of the installation most likely to be lost between handover and the first callback Electrical Equipment Working Clearance Space Calculator
- Isolators and terminations — the disconnecting means and the point the DC and AC runs land, which stand proud of the enclosure and eat into the clearance measured from the live parts
- Battery module — the only part quoted in kilowatt-hours, and the part whose permitted location and stated ambient band come from its own installation manual Battery Bank Sizing Calculator
- Bracket and fixings — carries the whole mass into the structure behind, which on a dabbed or studded wall means reaching past the lining rather than fixing into it Post-Installed Concrete Anchor Drill Depth Calculator
- Fire-resisting lining — the separation between the enclosure and whatever is on the other side, bought by the board and the roll of tape and almost never on the original quote Multi-Layer Fire-Rated (Type X) Gypsum Sheet Calculator
- Structural wall — masonry, block or studwork, and the thing that decides whether the fixing is a resin anchor, a frame fixing or a pair of new noggins
The room has a kilowatt-hour ceiling of its own
Capacity is normally settled before anyone thinks about position, which is the wrong way round when the position has a limit attached to it. Both NFPA 855 and the residential code's storage provisions cap what may be installed in a given location in a dwelling, individually and in aggregate, and manufacturers' own installation manuals often cap the number of modules that may be stacked or hung on one wall. The number that comes out of a sizing exercise is therefore a candidate, not an answer, until it has been checked against the room it is going in.
When the two disagree there are three moves and they cost different amounts. Take a smaller bank, which is a conversation about what the customer actually wanted the battery for. Split it across two positions, which is rarely as neat as it sounds because each position needs its own separation, its own clearance and its own run. Or change the room, which is usually the cheapest of the three if it happens at survey and the most expensive if it happens after the modules have arrived.
Size against what the battery is genuinely for. A grid-connected battery in a house with a supply that works is covering an evening and a morning, not a run of days, and the autonomy figure that suits a cabin with no connection produces a bank two or three times larger than this job needs. The neighbouring guide on off-grid banks works that measurement from a shunt and is the place to go if the property has no connection to fall back on.
Put the evening and overnight consumption in as the daily load and leave autonomy at a single day, then hold the nameplate it returns against the module count the chosen room and the installation manual will actually accept.
Energy used per day.
Days the bank must run with no charging.
Chemistry sets how much of the nameplate you can actually use.
Nameplate capacity required
11.7 kWh nameplate
Nameplate needed to deliver the stated usable energy. Real capacity falls with age and with temperature — a bank at 0 °C (32 °F) delivers materially less than its rating.
- Energy required at the load
- 10 kWh
- Usable share of nameplate
- 85.5 %
- Depth of discharge
- 90 %
- Round-trip efficiency
- 95 %
- At 48 V nominal
- 243.66 Ah
They open the calculator with your figures already in it
Battery Bank Sizing Calculator: 11.7 kWh nameplate — shown in imperial, US market. The link sets both, so the result they see is the one on your screen.
Add the equipment this sizes
This result is a specification — 11.7 kWh nameplate — not a quantity. Put the thing it sizes into your project: how many, what you call it, and your supplier’s price.
What this calculation does not cover
- Capacity fades over life. Most warranties guarantee 70-80% of nameplate at end of term, so a bank sized exactly today is undersized in year eight.
- Cold reduces available capacity substantially, and lithium cannot be charged below freezing without a heater.
- Says nothing about power. A bank with enough energy can still be unable to start a motor — that is a continuous and surge kW question, not a kWh one.
Two rectangles, and only one of them is in the code
Equipment that will need examining, adjusting or servicing while energised has to have somewhere for a person to stand, and the codes state that as a rectangle on the floor plus a headroom figure. Under NEC 110.26 the depth comes from a table indexed on voltage to ground and on what is opposite the equipment, the width is the greater of the equipment's own width or the code's floor of 750 mm and 30 in, and 110.26(A)(3) adds a separate minimum height to that working space, which is the clause people forget in a cupboard with a shelf over the door. BS 7671 does not print a rectangle, but it does require equipment to be arranged with sufficient space for installation, replacement and maintenance, which in an understairs cupboard or a narrow utility comes to the same argument with none of the arithmetic done for you.
The second rectangle is the manufacturer's, it is not in any code, and it is usually the one that bites. Installation manuals state a clear gap above, below and to each side of the enclosure, and often a larger one at the ventilation face, because the unit sheds heat by convection and because the covers have to come off for service. Those gaps are conditions of the listing and of the warranty. They are measured from the enclosure, not from the live parts, so they do not simply nest inside the code's working space, and on a stacked system they apply to the stack rather than to a module.
Mark both on the floor and on the wall with tape before anything is ordered, and then look at what shares the room. In a garage, open the car door where the car actually parks. In a utility, open the appliance doors and the room door together. In a cupboard, remember that the space belongs to the battery permanently and that a cupboard is the place a household stores things by definition, which is why the clearance needs to be written into the handover documents and, where it can be, physically defended with a rail or a plinth rather than described in a folder nobody opens.
Enter the enclosure width and the depth your voltage and installation condition demand, and you get the floor rectangle to lay out in tape — then draw the manufacturer's own gaps around the outside of it, because the two are measured from different faces.
The width of the electrical equipment (panel, switchboard, etc.) requiring working clearance in front of it.
The minimum clear depth required in front of the equipment, from NEC Table 110.26(A)(1) based on nominal voltage-to-ground and installation condition.
Required minimum working clearance area
7.38 ft²
Required depth depends on the equipment's nominal voltage-to-ground and the installation condition (1/2/3, based on what's opposite the equipment) per NEC Table 110.26(A)(1) — look up the correct depth for your specific installation rather than assuming a default. The width floor is stated by NEC 110.26(A)(2) as 750mm (30in) — two code figures, not a conversion of one another, since 30in is 762mm; the area here is worked from the 750mm figure, so if you are building to the imperial column allow the full 30in of width. Height clearance (2.0m/6.5ft minimum) is a separate NEC 110.26(E) requirement not covered by this floor-area calculation.
- Clear width used (NEC 110.26(A)(2) floor: 750 mm / 30 in)
- 30 in
They open the calculator with your figures already in it
Electrical Equipment Working Clearance Space Calculator: 7.38 ft² — shown in imperial, US market. The link sets both, so the result they see is the one on your screen.
What this calculation does not cover
- Gives a floor area, not the volume that has to stay clear. Above a switchboard or panelboard, NEC 110.26(E) keeps that same footprint dedicated to electrical use up to 1.8 m (6 ft) above the equipment or to the structural ceiling — no piping, no ducts, nothing foreign to the installation. A duct routed over the panel fails the room after the clearance in front of it was got right.
- Ignores what swings into the space. NEC 110.26(A)(2) requires the width to allow equipment doors and hinged panels to open at least 90 degrees, and a room door that swings back across the working space eats it. This is a clear floor area, not a strip that people, doors and storage may share.
A cupboard is a box with a heater in it
Every watt that does not come back out of the system leaves as heat into whatever room it is in. On a domestic installation the conversion and storage losses together run at a few per cent of throughput, so a unit working hard on a summer afternoon or on a cheap-rate overnight charge is putting a few hundred watts into the room, continuously, for hours. In a garage that is nothing. In a sealed cupboard with a boiler already in it and a door that is closed from October to April, it is a genuine temperature rise, and the equipment responds to it by derating, which the customer experiences as a system that mysteriously charges slower in the middle of a good day.
The arithmetic is a single multiplication — apparent power rating times the loss fraction — and the heat load calculator below does exactly that. Be aware of what it was written for before you use it: it is a dry-type transformer tool, its input floor is 15 kVA, and it assumes the one-to-two-per-cent loss band that distribution transformers achieve. It fits the shared plant room directly, which is where this question is hardest anyway — a communal battery serving a block, or a three-phase farm installation — and for a single 5 kVA domestic hybrid you are below its floor and the multiplication is one line on a phone, using the efficiency figure from that model's datasheet rather than a transformer's.
What you do with the watts is the part that belongs at survey rather than at commissioning. A cupboard needs a way for warm air to leave at high level and cooler air to arrive at low level, and grilles in a door are a real and cheap answer as long as they do not compromise whatever fire performance that door was there to provide — which, on a cupboard containing a battery, it usually was. Mechanical extract is the fallback and it brings a fan, a supply and a noise source into a plant cupboard. Either way it is a line on the quote, and it is decided by the room, not by the battery.
Written for a dry-type transformer and floored at 15 kVA, so it lands squarely on the communal or three-phase plant room; for a single domestic hybrid below that floor, take the same multiplication of rating and loss percentage from the unit's own efficiency figure.
The transformer's nameplate kVA rating.
The transformer's combined no-load and load losses as a percentage of its kVA rating.
Estimated transformer heat load
25,600 BTU/hr
Actual transformer losses vary by manufacturer, loading level, and transformer design — use the manufacturer's published no-load and load loss data at your specific operating load for a precise HVAC design calculation; this is a preliminary estimate for ventilation sizing only.
- Heat load in watts
- 7,500 W
They open the calculator with your figures already in it
Electrical Room Transformer Heat Load Calculator: 25,591 BTU/hr — shown in imperial, US market. The link sets both, so the result they see is the one on your screen.
Add the equipment this sizes
This result is a specification — 25,600 BTU/hr — not a quantity. Put the thing it sizes into your project: how many, what you call it, and your supplier’s price.
What this calculation does not cover
- Covers the transformer and nothing else in the room. Switchgear and panelboards, busway, drives, and above all a UPS with its charger dump heat into the same enclosed space, and where there is a UPS that equipment commonly outweighs the transformer. Ventilation sized on this figure alone runs the room hot.
- A heat figure is not a ventilation rate. Airflow comes from this heat divided by the temperature rise you are allowed above the outdoor design condition, and that allowance is set by the lowest maximum ambient in the room — around 40 C for the transformer, far lower where battery life matters. Halve the allowable rise and the fan doubles.
- The loss percentage is a rated-condition figure measured on a clean sinusoidal load. Non-linear load from drives and switch-mode power supplies drives harmonic currents that raise winding and eddy losses beyond the nameplate percentage, which is the whole reason K-factor and harmonic-mitigating transformers exist. On a data or lighting-heavy load the real heat runs above what this returns.
The runtime you quoted was quoted at twenty degrees
Backup duration is the number customers remember from the sales conversation, and it was almost certainly worked out at room temperature. Capacity falls as a cell gets colder and the effect is not small in an unheated garage in a British January, where a run of days below freezing is ordinary. Most lithium iron phosphate systems will discharge well below zero and refuse to charge below it, so a garage battery in a cold snap can be a battery that quietly stops taking a charge on exactly the mornings the customer is watching it most closely. A heated module solves that by drawing power from the pack to warm itself, which is real consumption that belongs in the winter figure and not in a footnote.
The honest thing to do at survey is to recompute the promise at the temperature the chosen room actually reaches, and the lever to move is the efficiency term rather than the capacity, since that single field is where depth of discharge and conversion losses already live. Do it twice, at the warm room and at the cold one, and put both answers in front of the customer next to what the two positions cost. That comparison decides more battery positions than any argument about tidiness, and it is far more persuasive than a sentence about temperature coefficients. The chemistry underneath it — why a pack refuses charge in the cold, what that does over a life — is worked through on the off-grid guide and does not need repeating here.
Run the same essential load twice, once with the efficiency you would expect in a heated utility and once with the cold-garage figure from the datasheet's capacity curve, and quote the customer the second one.
The total energy storage capacity of the battery bank.
The total wattage of everything running off the battery.
Inverter losses AND the battery usable depth of discharge, multiplied together.
Estimated runtime
5.67 hours
Real-world runtime varies with battery age, temperature, and how deeply it's safely discharged (especially for lead-acid batteries, which shouldn't be fully depleted) — check your specific battery manufacturer's guidance.
- Usable energy
- 1,700 Wh
They open the calculator with your figures already in it
Battery Backup Runtime Calculator: 5.67 hours — shown in imperial, US market. The link sets both, so the result they see is the one on your screen.
What this calculation does not cover
- Assumes the load is constant for the whole discharge. Anything that cycles - a fridge compressor, a well pump, a heat pump - draws its full watts only part of the time, so a runtime worked out from summed nameplates comes out far shorter than the bank really delivers, while one worked out from an average hides the peaks. The inverter's own standby draw also continues whether or not anything is switched on, and it is not in the figure unless you add it to the load.
- Runtime is an energy answer and says nothing about whether the system can carry the load at all. Whether the inverter and the battery can supply the continuous watts, and the starting surge of a motor or compressor, is a separate power question this calculation does not touch.
- Takes the bank as fully charged with nothing recharging it. No solar, generator or grid contribution is in the figure, and a bank already part-discharged when the outage began gives proportionally less than the runtime shown.
- The efficiency figure is fixed for the whole run. Capacity lost to cold, capacity faded over the bank's life, and the extra loss a lead-acid bank takes when it is discharged fast all have to be built into that one number yourself - no correction for temperature, age or discharge rate is applied.
- This is not a standby-battery compliance calculation. Fire alarm, emergency lighting and similar life-safety batteries are sized by a prescribed multi-stage calculation with its own derating and recharge requirements, set by the governing standard and the panel manufacturer's own sheet, and a general runtime figure does not substitute for it.
One box or two, and which end takes the long cable
How far the battery may sit from everything else depends on an architectural decision inside the product, and it is worth establishing before the first position is even proposed. A direct-current coupled hybrid puts the array, the battery and the grid connection through one converter, which is efficient and tidy and ties the battery to the hybrid by a short, heavy DC link whose maximum length is stated in the installation manual. An alternating-current coupled battery brings its own converter, connects on AC like any other circuit, and can therefore go where the building allows rather than where the hybrid is — at the cost of an extra conversion, an extra box and an extra circuit.
The reason the DC link is short is current. A battery working at a nominal fifty volts and discharging five kilowatts is pushing something in the order of a hundred amps, and copper at a hundred amps over a long run is expensive, heavy, awkward to terminate and unforgiving of a mediocre crimp. The same five kilowatts on a single-phase AC circuit is roughly a fifth of that current, which is why the AC side is the one that tolerates the run across the house. So if the good position for the battery is thirty metres from the board, an AC-coupled arrangement is very often what makes that position affordable, and that is a product decision taken at survey rather than a wiring decision taken on the day.
Sizing still has to happen, and on this job it is sizing for a physical reason as much as an electrical one. The AC rating of the converter that goes on the wall determines which enclosure you are hanging: the difference between a light convection-cooled unit and a heavier fan-cooled one changes the fixing, the clearance, the heat into the room and whether one person can hold it against the wall while the other starts the bolts. Fix the rating, then look up that model's mass and dimensions, then decide whether the wall you chose can take it.
The connection route is a separate matter and it runs on its own clock, because what the network is assessing is what the installation can push outward — which on a hybrid may be the battery discharge figure rather than the array. That whole question, including which document sets the threshold and when the paperwork happens relative to commissioning, is covered on the grid connection guide, and it should be settled in parallel with the position rather than after it.
It works the AC rating from the array's DC nameplate, so it answers the hybrid case directly; on a battery-only retrofit with no array the rating comes from the discharge figure instead and this is only a sanity check. Either way, take the rating to the datasheet for the mass, the dimensions and whether the unit is convection or fan cooled — all three of which the position has to accept.
Total nameplate DC watts of the panels.
How much larger the array is than the inverter.
Soiling, wiring, mismatch, temperature and inverter efficiency.
Inverter AC rating
5,000 W AC
Capacity sizing only. String voltage limits, MPPT window, temperature coefficients and the local wiring rules all constrain the final selection.
- Inverter rating
- 5 kW AC
- Array DC rating
- 6 kW DC
- Realistic peak AC after losses
- 5.16 kW
- Headroom over realistic peak
- -3.1 %
They open the calculator with your figures already in it
Solar Inverter Sizing Calculator: 5,000 W AC — shown in imperial, US market. The link sets both, so the result they see is the one on your screen.
Add the equipment this sizes
This result is a specification — 5,000 W AC — not a quantity. Put the thing it sizes into your project: how many, what you call it, and your supplier’s price.
What this calculation does not cover
- Does not check string voltage against the inverter's MPPT window or its maximum input voltage — cold-weather open-circuit voltage is what breaks inverters and it depends on the panel's temperature coefficient.
- Does not consider grid export limits, which in several markets cap the inverter rather than the array.
- Shading is not modelled. Partial shading is better addressed with optimisers or microinverters than with sizing.
Getting a hundred kilograms to the chosen wall
A domestic battery module is commonly somewhere between fifty and a hundred and twenty kilograms, and a stacked system with its base and converter is a good deal more than that concentrated over a small footprint. That is a two-person lift at best, it is a two-person lift at chest height against a wall, and it has to travel from the van to the position through whatever the house provides. Measure the route, not the room: the front door, the turn at the bottom of the stairs, the width of the side passage, the garage door if that is the only way in, and the height of the threshold. A unit that will not go round the turn on the stairs has ruled out every position above the ground floor regardless of what any code says.
In the roof space this becomes the dominant objection and it is worth being blunt about with a customer who has their heart set on it. A standard loft hatch is a hole a person fits through, not a hole a hundred-kilogram box fits through, and the lift is overhead, from a ladder, into a space with no floor except where somebody boarded it. Then there is the structure: a trussed rafter roof is designed for a ceiling, insulation and light storage, and a point load of this order sitting on two bottom chords is a question for someone competent to answer against Eurocode 1 or ASCE 7 imposed loads, not a question to settle by standing on the joist and deciding it feels solid. And the position has to be serviceable for twenty years, in a space that gets hot enough in summer to be genuinely unpleasant to work in.
The fixing itself is short work done badly more often than it is done well. Establish what is behind the plaster before the bracket is offered up, because a dabbed board over blockwork wants a fixing that reaches the block and accounts for the void, a timber stud wall wants noggins let in between the studs at the bracket centres rather than a hopeful pair of plasterboard anchors, and a resin anchor in masonry wants the hole cleaned properly or it is a decorative fitting. Where the wall has just been lined for separation, the bracket has to pass through that lining without compromising it, which is a detail to plan rather than to improvise with a hole saw.
- Walk the delivery route with a tape before quoting, and record the narrowest point and the tightest turn on the survey sheet.
- Confirm the shipping weight of the heaviest single item, not the system weight, and decide there and then how many people are on the job.
- For anything above ground floor or in a roof space, establish what the structure is and get the point load assessed by someone competent rather than assumed.
- Identify the wall build-up by drilling a test hole in the position, and choose the fixing from what comes out on the bit.
- Check the manual handling arrangements against the Manual Handling Operations Regulations in the UK, or the NIOSH lifting equation where that is the reference in use, before the day rather than in the driveway.
- Where the position is in a roof space, treat the work as work at height with the access, boarding and edge protection that implies.
Noise, and the bedroom on the other side
A battery system makes three kinds of sound and only one of them is obvious. There is fan noise, which comes and goes with load and temperature and is the one people expect. There is a steady electrical hum from the magnetics, which is quiet but continuous and is the one that keeps a light sleeper awake through a wall. And there is the mechanical click of a transfer relay if the system carries a backup circuit, which happens at whatever hour the supply hiccups and is loud in a silent house.
So look at what is on the other side of the chosen wall before committing to it, and treat a shared wall with a bedroom as a reason to move rather than as something to manage. A garage gable, a utility with a solid wall to a hallway, or an external elevation are all straightforward. A stud partition to a child's bedroom is a callback waiting to be booked, and no amount of foam applied afterwards fixes structure-borne hum. This is not a code question anywhere and no document will help you argue it, which is exactly why it has to be raised while the customer is still choosing.
What goes on the survey sheet before you leave
The position is a decision with about eight inputs and none of them survive the drive home. Write them down in the house, take photographs of each candidate wall with a tape in shot, and mark the chosen rectangle on the floor before you pack up. The point of the list is that anybody reading it afterwards can see why one wall was chosen and the other three were not.
- The chosen room and the wall within it, photographed, with what is on the other side of that wall recorded.
- The separation already present and the separation still to be built, priced as boards, fixings and labour rather than left as a note.
- The floor rectangle from the code's working space, plus the manufacturer's own clearances, both marked on site and both dimensioned on the sheet.
- The wall build-up as found by a test hole, and the fixing type that follows from it.
- The measured route from the van to the position, with the narrowest point, and the decision on how many people the lift needs.
- The DC link length against the manual's maximum, or the decision that this is an AC-coupled system and why.
- The ambient range the room actually sees, against the operating and charging bands in the installation manual, with the cold-case backup runtime worked and shown to the customer.
- The ventilation provision for the heat, and whether it can be achieved without breaching the door or wall the separation depends on.
The eight lines that fix a position
Every one of these is answered in the house with a tape and a torch, and every one of them becomes a variation order if it is answered afterwards. Separation heads the list for the same reason it heads the walk-round: it is the one answer a longer cable cannot buy back.
- Separation present and separation to be built — What the wall, ceiling and door already are, against what the adopted specification requires between the enclosure and habitable space or an escape route.
- Clear working space, marked on the floor — The code rectangle in front of the equipment, and the manufacturer's gaps around the enclosure, laid out in tape with the car door and the appliance doors open.
- The room's own capacity ceiling — Per-location and aggregate limits from the adopted code, and the module count the installation manual permits on one wall. Checked against the sizing answer, not after it.
- Ambient range, measured or reasoned, for that room — Winter low and summer high, held against the operating and charging bands in the manual. The backup runtime is then quoted at the low one.
- Heat out of the room — Rating times loss fraction gives the watts; the answer is high-level and low-level ventilation that does not defeat the fire-resisting door it passes through.
- DC link length, or the decision to couple on AC — The manual's maximum for the heavy short run. If the good position is beyond it, the product changes, and that is a survey decision.
- Wall build-up and fixing, from a test hole — Dabbed board, stud or solid, with the bracket fixing chosen from what the drill finds and detailed to pass through any new lining intact.
- Delivery route and lift plan — Narrowest point, tightest turn, heaviest single item, and the number of people. A hatch a module will not pass through eliminates the roof space on its own.
Opens the calculators above on one screen with the dimensions from this article already filled in. Quantities only — this site publishes no price list, because local prices vary too much to publish honestly.