Do I need to replace my fusebox?

NewFolder

I have a MEM Memera 3 Fuse Box.

It has 4 fuses in it: 5A for lighting, 15A for 'Heating' (I think it means immersion heater, I don't think a timer and pump will draw 15A), 30A for the ring main, and a 15A for the cooker outlet. The fuses are cartridges with fuse wire inside them.

There is a CU in the loft, with a RCD and two MCB's. One MCB supplies the electric shower, and the other supplies one double socket in the loft (AFAIK it doesn't supply anything else).

I'd like to know whether this setup is dangerous or it should be replaced. The house was built in 1985, and we've been living there since 2005, and in that time, we've only had to replace two fuses, once because some guy tried to replace some wall lights and wired them up wrong (idk how) and caused a short circuit. The second time was when a shed installer decided to try to disconnect and move the shed socket without asking us to switch off the electricity first. Fortunately, he managed to blow up the fuse instead of himself!

Might it be better to just keep the current system and perhaps use those plug in RCDs on certain appliances?

Does anyone know around how much it would cost to replace this fusebox with a modern consumer unit with MCBs and RCDs, bearing in mind that there are only 4 outputs?

If anyone needs any more information please ask.

Ben84

What now makes you worried about it?

Anyway, in general terms, if it's in decent condition, was installed properly when new, hasn't had bodged DIY work on it and you're not overloading it, then everything should be fine. The safety standards it met in 1985 are still valid and they were perfectly good standards at the time as far as I'm aware.

googler

I sold mother's house in 2010 - built in 1970, it still had the original fusebox; and you're worrying about one from 1985.....

NewFolder

Ben84 wrote: »

What now makes you worried about it?

Anyway, in general terms, if it's in decent condition, was installed properly when new, hasn't had bodged DIY work on it and you're not overloading it, then everything should be fine. The safety standards it met in 1985 are still valid and they were perfectly good standards at the time as far as I'm aware.

It's just that it looks ancient, a lot older than any other fusebox I've seen, apart from on really old houses. It also doesn't have RCD protection which isn't great for outdoor equipment along with other stuff.

I've heard in various places that electricity safety standards change a lot, and today's are a lot different than even like 10 years ago.

Would a fuse wire melt as quickly as an MCB would in the event of an overload?

I haven't really had any problems with this house's electrical system, apart from faulty substations causing frequent power cuts a few years ago, but that's sorted now. Perhaps I could just use plug-in RCDs with outdoor equipment?

googler

NewFolder wrote: »

I've heard in various places that electricity safety standards change a lot, and today's are a lot different than even like 10 years ago.

A change in regs or standards does not, of itself, render any previous installation unsafe, merely non-compliant with a new set of standards.

They changed the standard colours of mains wiring recently; new installations have to use the new colours - do you think anyone should be ripping out their old wiring to install the new?

Laz123

Personally I'd replace it with a consumer unit. It's a lot safer and you won't go up in a puff of smoke if you have an accident as it'll trip out before you die.

spotlight_elec

Naturally being a electrician i would change the board because

• Additional protection against fire
• Electric shock

to current regulations (17th Edition) it is a requirement that every circuit should be protected by a rcd.

A consumer unit would cost in the range from £300 upwards.

Ben84

NewFolder wrote: »

It's just that it looks ancient, a lot older than any other fusebox I've seen, apart from on really old houses. It also doesn't have RCD protection which isn't great for outdoor equipment along with other stuff.

I've heard in various places that electricity safety standards change a lot, and today's are a lot different than even like 10 years ago.

Would a fuse wire melt as quickly as an MCB would in the event of an overload?

I haven't really had any problems with this house's electrical system, apart from faulty substations causing frequent power cuts a few years ago, but that's sorted now. Perhaps I could just use plug-in RCDs with outdoor equipment?

As far as I'm aware, fuses typically blow faster than most circuit breakers. I actually prefer fuses as they have no moving parts and cannot wear out or malfunction. A fuse can sit there for decades just being ignored until needed. However, I believe both are suitable to protect circuits from most common faults and am not suggesting circuit breakers are normally dangerous.

Anyway, the purpose of a fuse or breaker is to protect the circuit - which indirectly protects you from encountering a shock, but I wouldn't say that they protect you specifically from the effects of an electric shock. Usually protection from shocks is built in to appliances by having no exposed metal parts, or by earthing any so that during a fault that electrifies these parts the electricity takes that path to earth and blows the fuse/breaker. However, if despite the best attempts of appliance designers you touch a live source, I don't believe a fuse or breaker will normally respond. At any rate, I've never known a fuse or breaker be activated by someone getting an electric shock. This is where an RCD comes in, it does offer you more protection as it measures the electricity on both the live and neutral and if it doesn't match, it trips. So, it can detect electricity escaping the circuit and that means it can tell when someone gets an electric shock and trip (as well as other faults that may damage appliances or cause overheating).

I use an RCD plug in unit for outside electrical items like the lawnmower and pond pump to offer better safety than my 1960s wiring with fuse box does. However, having it for the whole circuit with a unit in the fuse/breaker box would be good too. Still, I don't feel unsafe with my electrics just because they don't have an RCD. So, while I like RCDs and see good reasons to have one, I'm not suggesting your existing wiring is innately dangerous either. If it was installed properly, it does have many safety features and using it properly (no overloading things or using dubious quality appliances like phone chargers from market stalls for example) will make you a lot safer too.

Personally, I'll probably get a new circuit breaker box with RCD in the future to make things safer, but I'm not considering it a dire urgent need either.

DVardysShadow

Ben84 wrote: »

As far as I'm aware, fuses typically blow faster than most circuit breakers. I actually prefer fuses as they have no moving parts and cannot wear out or malfunction. A fuse can sit there for decades just being ignored until needed. However, I believe both are suitable to protect circuits from most common faults and am not suggesting circuit breakers are normally dangerous.

I go along with this - with one caveat. Rewireable fuses [ceramic holder which you renew with wire wound around a card] are too tolerant of low level overloads and you can never be sure that the correct wire has been used.

Cartridge fuses to BS1361 in a consumer unit are fine and to my mind preferable to MCB's for the reasons you give.

Ben84

DVardysShadow wrote: »

I go along with this - with one caveat. Rewireable fuses [ceramic holder which you renew with wire wound around a card] are too tolerant of low level overloads and you can never be sure that the correct wire has been used.

Cartridge fuses to BS1361 in a consumer unit are fine and to my mind preferable to MCB's for the reasons you give.

You've made a good point, fuse boxes have much more potential to be misused than circuit breakers. People can put in the wrong fuse wire, or even just a bit of metal. Some designs also allowed you to turn them on while open and had exposed live parts. If you use them properly, they're fine, but for whatever reasons, that doesn't always happen.

I think a lot of people also prefer the whole flipping a switch rather than hunting for fuse wire and taking things apart too.

However, wylex do still make fuse holders for use with cartridge fuses for consumer units, so fuses are presumably still being used for some installations. When I do get a new consumer unit I might go with that option rather than circuit breakers. I just don't want to have a circuit breaker that's supposed to be tested every few months as I know I'll just close the lid and forget about them. At least with fuses that's what you're supposed to do.

John_Jizzle

we bought a house that had an oldish fuse box (90s i think). It was legal to sell it to us BUT when we went to change our main light to spotlights we were told we would need a new fuse box as they no longer meet regulations (if new work to be done)

luckily it was a friend so he didnt change the fusebox (£300 job) but a normal electrician would have or walked away