Video reference. John Ward (jwflame) gives a detailed walkthrough of a Wylex 1960s rewireable fuse board in his video "Retro fuse box but does it work? Wylex 1960's fuse box overview. Old UK domestic wiring." John is a UK-based electrician with an extensive catalogue of UK-specific electrical content. Worth watching if you have one of these boards and want to see exactly what is inside.
1. Identify your fuse board type
Open the cover of your fuse board and look at the devices inside. A rewireable fuse board has a row of ceramic or Bakelite fuseholders, each a different colour corresponding to a circuit rating. The most common makes in UK homes are Wylex Standard (cream or white), MEM (grey or cream), Crabtree and Contactum.
To confirm it is rewireable rather than MCB-based: pull out one fuseholder (the main switch must be off first, though that does not make the board fully dead). You will see a small ceramic bridge with a groove and two brass clips. The thin wire threaded through the groove is the fuse wire.
2. Understand how a rewireable fuse works
A length of fuse wire, rated at either 3, 5, 15, 30 or 45 amps, carries the full current for that circuit. If the current rises above the wire's rating, the wire heats up and melts, breaking the circuit. That is the entire protection mechanism.
There is no electronic element, no trip mechanism, and crucially no residual current detection. If a live conductor touches earth (a fault to earth rather than a short circuit), a rewireable fuse may not blow at all if the fault current is too low to melt the wire. A modern RCD or RCBO detects a leakage as small as 30 milliamps and trips in 40 milliseconds -- a rewireable fuse has no equivalent protection.
3. Check the fuse wire ratings
Each fuseholder should have its rating printed or embossed on it: 5A for lighting circuits, 30A for socket ring mains, 45A for cooker circuits, 15A or 20A for immersion heaters. Check that the wire colour (or a label on the holder) matches the rating you would expect for that circuit.
If you find thick copper wire or silver foil in a fuseholder instead of proper fuse wire, that circuit has been made permanently live by someone who should not have done that. Call an electrician before using those sockets or lights again.
4. Look for the three warning signs
Check the outside of the board for any of these:
- Scorch marks or discolouration around any fuseholder -- a sign of arcing or overheating.
- A burning smell from the board, especially after a fuse has blown.
- A fuse that blows repeatedly -- something on that circuit is drawing more current than the wire can carry, and finding out why matters before replacing the wire again.
If any of these are present, do not just replace the fuse wire and carry on. Call an electrician.
5. Understand what current regulations say
BS 7671 does not require existing boards to be replaced immediately simply because they are old. However, two practical pressures often force the issue. First, if you want any new electrical work done (a new socket circuit, an EV charger, an EICR for a rental property), the work must comply with current regulations, which require 30 mA RCD protection. An old rewireable board typically cannot accommodate this without replacing the whole board.
Second, some household insurers and most conveyancing solicitors now flag old rewireable fuse boards when a house is bought or sold, and a quote for replacement is commonly requested before exchange of contracts.
6. Consider whether an upgrade is right for you
A modern consumer unit -- typically a split-load board with two RCDs protecting groups of circuits, or an all-RCBO board giving each circuit its own device -- costs from roughly £500 to £900 fitted in east Kent. The job takes half a day for most houses and includes an Electrical Installation Certificate and a notification to building control under Part P.
Before you call, it helps to know how many circuits you have (roughly one per fuseholder) and whether any previous work on the wiring has been certified. The electrician will want to check the earthing arrangement and the condition of any older cables before committing to a price.
When to call us
If your home has an old rewireable fuse board and you are thinking about an upgrade, or if an EICR or house sale has flagged the board, Richard can visit, assess the existing wiring and give you a written quote. There is no charge for the visit if work goes ahead. Sandwich and east Kent covered.
Thinking about upgrading your old fuse board?
Richard fits consumer units across Sandwich and east Kent. Call or message for a no-obligation quote -- he will check the earthing arrangement and condition of your wiring before committing to a price.
Contact Richard