Electrical — the supply upgrade

The electrical question

• Nothing ever runs all at once, and a real assessment applies diversity — but the shape is clear. On a 60 A supply this is tight; on 80 A it works with the hob managed; unmanaged it is over.
• The hob’s power management is the whole trick. Setting it to 16 A takes 3.7 kW off the top and is usually what makes an all-electric flat work without touching the incoming supply. Worth confirming you are happy with the reduced boost performance before relying on it.
• Find the fuse rating — see below. The photos show 100 A rated gear, which is encouraging, but it is not the same as a 100 A fuse.

What the meter cupboard shows

• The 100 A on the cutout is the carrier rating, not the fuse rating. Those are BS 1361 Type II service heads — the body is rated to take up to a 100 A fuse. The element actually fitted inside could be 60, 80 or 100 A, and you cannot tell from outside. Same with the Wylex switch-fuses: “100 A AC22A” is the switch’s rating, not your supply.
• So the photo does not answer the question — but it does de-risk it substantially, which is the more useful outcome.

• The building’s switchgear is already 100 A rated throughout. Cutout carriers, switch-fuses, the lot. That strongly suggests the service cable is sized for 100 A too.
• Which matters because it changes the worst case. If your fuse turns out to be 60 A, uprating it is likely a fuse change by the network operator rather than a new service — days to weeks, often at little or no cost. A full service upgrade with new cabling is the months-long job, and the 100 A infrastructure makes that much less likely.
• At 100 A you have 23 kW, and the electrical constraint on this project essentially disappears.

How to actually find out

• Work out which cutout is yours first — trace from your meter back. There are more meters than flats in that cupboard, including what looks like a communal or hall supply, so do not assume.
• Look for a rating label on your cutout carrier. Many are marked, often colour-coded, sometimes only visible from an angle.
• Otherwise ask the network operator — they hold the record and it is a free enquiry. Call 105, which routes to whoever runs the network in your area, and ask for the fuse rating at your address and whether it can be uprated to 100 A.
• Do not pull the cutout to look. It is the network’s equipment, it is sealed, and it is live upstream of everything.

Two things worth noticing as a director

• That intake is old and untidy — meters dated 2006–07, Wylex switchgear to a 1977 standard, handwritten labels, and one modern smart meter dropped in among it. None of that is your flat’s problem directly, but it is the freehold company’s asset and it is worth an inspection at some point.
• If the other three flats eventually go all-electric too, the building’s total intake becomes a shared question. You are first on the heat pump; you may also be first to find out what the incoming capacity really is. Worth passing on what you learn.

Circuits this project creates

Worth deciding now while floors are up

• EV charging. Not mentioned, but if it is ever likely, a duct and a cable route to the garden or the front costs almost nothing now and is disruptive later. It also changes the supply sum materially.
• Solar and battery. Same logic — a route to the roof and space near the consumer unit. You are a director of the freehold company, so the roof conversation is one you can have.
• Network cable runs. The comms cabinet is at the front of the house and the tech cupboard is on the party wall. Pull spare cable while the floor is open.