Replacing fuse wire with RCD - youtube video

That should say "That is NOT exactly the same as the fuse here."

Do not piss about with MCB replacements unless you have to [1], swap the fuse box for a RCD protected CU.

Waiting for a picture, but there looks to be a new RCD protecting the old CU.

I didn't understand what was going on because I didn't have time to trace everything through, but there is some new stuff and the old CU.

At the moment I am looking at making resetting a blown fuse easier. I don't have the time to undertake a CU replacement and funding an electrician to do this is well down the pecking order at the moment.

Just trying to estimate if a stop gap is worth doing.

Thanks

Dave R

RCBOs Shirley? You don't want the entire supply brought down because of a fault on one circuit.

I'd be a lot happier about offering advice,if I thought you knew the difference between fuses, mcb's rcd's and rcbo's The opportunities for creating mayhem are wondrous

A split load RCD CU is a minimum. Ta for pointing that error of mine out.

For a one off on one circuit go for it.

Perhaps you could provide some clarity?

You've not shown us the current fusebox, nor the RCD/ELCB/whatever providing some unknown level of shock protection. So nothing conclusive can be offered really.

MCB vs fusewire: MCBs are easy to reset, more prone to false trips. Fusewire can be abused. MCBs are the choice for rented properties - no call outs, no dangerous miswiring by some drunk, no risk of handling live bits.

RCBOs can't be retrofitted to most rewirable fuse boxes.

MCBs are a couple of quid on ebay, so not much to lose.

NT

I'll let you know if a fuse ever blows, its only been 30 years so far.

Usually true...

That's a good argument for modern MCBs - but not retrofitting them to an old wylex CU.

Its a fair assessment of the situation IMHO.

Not really - since it does not address most of the shortcomings of those old style fuse boxes i.e. lack of adequate numbers of circuits for a modern install, and no way to incorporate RCD protection. You may also find (depending on the age of the cables) that the BS3036 fuses might leave some circuits without adequate fault protection (especially spurs on ring circuits using a 1mm^2 earth or imperial equivalent)

About the only time it might be worth retrofitting would be on a lighting circuit in a property where there are old or inform users, you don't want the disruption of a CU replacement and there are still lots of filament bulbs in use, and so there is some possibility of a nuisance fuse blow on a lamp failure.

Of course its easier and if there is a fault you can have a days work for you to find it if it blows the fuse every time. I never understood why old fuses did not use a cartridge like plugs and appliances did, Seems strangely retro even all those years ago and hands up those who have used strands from stranded wire and a bit of guess to mend them when you misplace the roll of fuse wire. Brian

1. You could get cartridge fuses to fit some CUs
2. I suspect that when wire fuses were first brought in, cartridge fuses hadn't been invented

My parent's, house built in the 50's had cartridge fuses.

It was all metal cases too.

Will post a picture when I get it.

Interestingly this is an ex-rental property which may explain the mix of ancient and modern, perhaps to ensure the electrician would sign off on safety.

Cheers

Dave R

Thanks - might suggest putting a trip switch replacement in the lighting circuit as a short term fix.

I don't think there are any filament bulbs; mainly CFL and perhaps a halogen or two. I started the process of replacement by LCD bulbs which has eliminated the "time to warm up" issue.

The fuse box will take 6 circuits (I think) and only has 4 populated. Lighting, power, shower and cooker I think. Again, I haven't had time to check. Could be two power (up and down) and the fan oven on 13 amp. However there does seem to be a dedicated cooker point.

Fitting a modern CU would fit in with other major works including expanding the number of sockets, splitting upstairs and downstairs 13 amp (if not already done), replacing and possibly moving the boiler.

None of this is likely to happen this year. Recovery from the costs of buying the house is likely to be first on the list, with anything that is working being left alone until later.

The electrics have been safety checked and signed off quite recently so hopefully there are no nasty surprises lurking.

Cheers

Dave R

Other lamp types are less likely to result in nuisance tripping anyway - so you could argue the re-wireable fuse is less of an issue anyway in this case.

Its sounds (from you other posts) as if someone has installed a RCD ahead of the CU anyway. While this does offer protection from electrocution, it brings a heightened risk of nuisance trips... It also loses "discrimination" i.e. the effects of faults being cleared are now no longer limited to one (or at least a sub set of) circuit(s). Lose one lose all.

(the reason use of "whole house" RCDs is deprecated)

In the circumstances, unless there is some other major reason for changing things, I would be tempted to leave it alone at this stage, and then do a full CU replacement (probably an "all RCBO" install) when funds etc permit.

MCB - miniature circuit breaker. A device designed to limit "overcurrent". They have two trip mechanisms, one thermal and one magnetic. The thermal trip will clear sustained long duration overloads. The magnetic part will respond quickly to very high "fault currents" (i.e. typically a short circuit between L & N or L & E). These perform the same job as fuses generally.

RCD Residual Current Device (aka Residual Current Circuit Breaker, Ground Fault Circuit Interrupter etc). Designed to interrupt power when an imbalance is detected in the current flowing in L & N. This detects situations where current is flowing to a earth from somewhere in a circuit. Since the majority of electrical shocks will result in this happening, they offer a significant reduction in the probability of serious injury or death from electrical shocks.

RCBO Residual Current Breaker with Overload Protection - basically combines a MCB and RCD together in one unit. These offer some notable advantages to installs using separate devices - notably, much better isolation of the effects of faults from other unrelated circuits.

See:

You say the electrics have passed an EICR, but from your description there is 1 RCD covering the whole install, which is NTCS. Most Wylex rewirables are also NTCS.

I presume the problem is repeat tripping. Getting rid of the filament lamps that are wasting your money may help. CFL & LED both save more money than they cost when replacing filaments. If the cause is something else, fuse or mcb won't solve it.

If you're really penniless, CFLs can be picked up on freecycle/freegle/gumtree etc. I don't recommend poundland LEDs.

NT

Thanks - my request was somewhat tongue in cheek.

My main reason for going to RCBOs was that RCDs can trip when the circuit is turned off at the MCB if you manage to bridge between Neutral and Earth. Which I have done on occasion. My limited understanding is that with an RCBO the breaker switches off both live and neutral but an MCB only switches off the live.

Then again, being somewhat acronym blind at times I could be wrong.

Cheers

Dave R