EV charger installation takeoff

A charge point is a charger fixed to a wall or a post by the drive, fed by a circuit of its own from the consumer unit (the service panel), and the first question is whether the house's supply can carry it at all. A charger draws its full current for hours at a time, so the electrician adds up what the house already takes at its busiest against the main fuse or the service's rating: where there is room, the charger is connected as it is; where there is not, it is set to hold back when the house is busy, through a current clamp on the incoming cable, or the network operator (the utility) upgrades the supply, which is its own work and excluded here. In Great Britain the network operator is told of the charger once it is connected, or asked first where the supply is tight; in the US the circuit is permitted work, inspected under the electrical code's article on EV charging (NEC Article 625), and in Canada under the Canadian Electrical Code's Section 86.

The rows follow the cable. It leaves a new way in the board, runs through the house, where the floors along its route are sheeted, goes out through a wall in a sleeved hole sealed behind it, and then either along the outside wall to a charger beside the drive or down into a trench to a post. In Britain it is usually armoured cable (SWA) clipped direct and laid in a duct where it is buried; in North America it runs in conduit, often EMT, with PVC below ground. The conduit page gives the route's developed length, its straight legs plus the curve of every bend, which is the cable's length either way. Where the route enters an integral or attached garage, the hole through the separating wall or ceiling is fire-stopped round the cable once it is through. A charger on a post needs the post held upright for years of cars pulling in beside it: it is bolted to a small concrete base cast at the trench's end or screwed into the ground, as the maker's instructions say, and that base is part of fitting the charger. Before any digging the ground is scanned for buried services; the trench is dug by hand, the duct laid with warning tape above it, and the trench backfilled with its own soil. Where it crosses a concrete drive, the concrete is saw-cut along both edges, broken out and filled back with new concrete to the surface; block paving is lifted and relaid and turf put back. Cutting and patching a tarmac (asphalt) drive is a surfacer's work, and excluded.

The electrical decisions are the electrician's, and each is listed here and never made. A charger outdoors on a supply whose neutral and earth are combined outside the house (PME, the common arrangement in Britain) needs either a device in the charger that cuts it off if that combined conductor is lost or an earth rod of its own, which is provisional until the supply has been examined. The circuit's protection against an earth fault is the line a charger's quote is worth reading for: in the UK the wiring regulations' section on EV charging asks for a Type B RCD, or a Type A where the charger detects a direct-current fault itself; in North America the electrical codes' EV charging rules ask for ground-fault protection for personnel. A switch that locks the charger off beside it is fitted where the charger has no isolation of its own or the rules ask for one, and the board is replaced where it has no spare way or cannot give the circuit that protection. The circuit is tested and recorded, the charger is set up on the owner's account, and the certificate, the notification and the acknowledgement are handed over.