Should I have a new CU installed?

[K-Duffy]

I recently moved into an old house that was generally in need of some TLC. Been ripping out carpets and stripping walls ever since being worried about asbestos etc but it’s been in the back of my mind that maybe the electrics are out of date.

How is this fuse board looking, unsafe? I always feel safe in a home where the electrics trip properly when something goes wrong. Is that an RCD protection? And in this case is that absent?

thanks everyone

 

[blup]

I think that's from the late 80's with what looks like wire fuses in a separate box, so worth uprating for protection to current standards. Specifiy rcbo's which give individual rcd protection to each circuit, useful if a circuit fails because others will not trip at the same time.

Your electrician would advise you on what's suitable for your property.

Blup

 

[K-Duffy]

I think that's from the late 80's with what looks like wire fuses in a separate box, so worth uprating for protection to current standards. Specifiy rcbo's which give individual rcd protection to each circuit, useful if a circuit fails because others will not trip at the same time.

Your electrician would advise you on what's suitable for your property.

Blup

thanks Blup! Worried I may have to rewire the whole house but definitely better to get that done now while it’s a pre-refurb mess (although we are still living in it)

What’s a typical price on rewiring a simple 3 bed semi? No fancy lighting or anything.


*edit* googled it and found the average is £5k and a few days work, woof!

 

[ericmark]

The old Wylex fuse box with MCB's fitted should have any MCB over 32 amp right next to the main switch as only that one had the extra reinforced clips. Also the main switch on most was rated 60 amp so it limits supply to whole house as DNO can't uprate their fuse if the isolator is only 60 amp. However they were a good box, and the electrical safety council says

so can't say it must be changed, but I would and did change the one in this house. I fitted a fusebox (that's the make) consumer unit with all RCBO's and a surge protection unit, seem to remember the bits cost me around £250 there are boxes with just two RCD's which are cheaper under £100 but fitting cost is the same and the problem with duel RCD's is one fault can trip half the house, and loose a freezer full of food and that is far more then the extra to fit all RCBO's, so really silly to fit twin RCD's.

Oh a RCBO is a RCD and MCB combined.

As to surge protection device, (SPD) I fitted one, but not really convinced it was required. The idea of the SPD is to protect semi conductor devices which are directly connected to mains, years ago mains when into a transformer and then to semi conductors and the transformer would stop most surges or spikes, today mains is turned into DC then into AC at high frequency then transformed down so semi conductors are connected direct to the mains. Even things like the LED light bulb could in theory be damaged by a spike.

But I have not heard of many homes where a whole load of bulbs have failed together so not convinced there is a real need for the SPD, with fusebox make around £30 so not worth taking a chance, with some makes however looking at a £100, so wait and see what others say about them.

The biggest problem when adding RCD protection is it finds out existing problems, it happened with my mothers, we were having a wet room done, and the guy doing the electrics said rather than fit a second consumer unit for the wet room with RCD protection I can change the existing for an extra £100 which seemed a good deal, however when I arrived he could not get the RCD to hold in, and ended up fitting an isolator so only half the board protected.

You don't clearly want these problems, specially as freezer not working while he sorts it, so the electrician should test before he starts, and he may say other work needs doing first. This house also had a problem, but since all RCBO it was only with two circuits, and I soon found problem and corrected.

It took me 6 months to get around to the upgrade, yes the RCBO has tripped for a genuine fault, the roof leaked and water got into a socket, but no false trips. And with all RCBO's I could wait until roof repaired before re-energising that RCBO, had I only had two RCD's then it would have caused all sorts of problems.

 

[flameport]

the average is £5k and a few days work

5K would be a low end starting price for a proper rewire, and unless there was a team of several people doing it, it will take a lot longer than a few days.

The fusebox is obsolete, meaning you can keep it exactly as it is if you want, but you can't add any circuits or extend any of the existing ones.

Whether a rewire is needed depends on various factors. Either way, that old fusebox needs to be replaced.

 

[plugwash]

How is this fuse board looking, unsafe? I always feel safe in a home where the electrics trip properly when something goes wrong. Is that an RCD protection?

In general in electrics we have layers of protection, to simplify slightly:

The first layer of protection is the basic insulation.

The second layer of protection is the combination of earthing with over current protection.

RCDs are a third layer of protection. Newer editions of BS7671 have steadilly increased the number of situations in which they are required, so under current BS7671 most domestic circuits are required to be protected. As an owner occupier you aren't under any legal obligation to update your installation to current standards, but you may find it difficult to find electricians who are prepared to extend a circuit without RCD protection.

And in this case is that absent?

Indeed there is no RCD protection in your current setup.

 

[plugwash]

the electrical safety council says View attachment 263523

They do say that, but they also say that "Absence of RCD protection for portable or mobile equipment that may reasonably be expected to be used outdoors" is a C2 and hence will result in an "unsatsifactory" result on an EICR.

There are undoutablly some flats, where use of portable equipment outdoors from a socket in the flat is unlikely, but for a house or ground floor flat I think it can be reasonablly assumed that at least some sockets will be used to supply equipment outdoors and hence a total lack of RCD protection is likely to result in an "unsatisfactory" EICR.

Now it would certainly be possible to add RCD protection to sockets used to supply equipment outdoors without replacing the CU, but I don't think it's sensible. Adding RCD protection before the CU would leave you with a single RCD protecting almost everything, which is troublesome if it trips. Adding RCD protection after the CU is ok if you only need to protect a single circuit, but if you want to protect most/all circuits it's going to get very messy and be more work than just replacing the damn CU. I guess you could add a RCD for the downstairs sockets only and get a minimally "satisfactory" result, but you would still be left with an installation that was problematic to extend/modify in future.

 

[EFLImpudence]

Not arguing with you Plugwash, but:

They do say that, but they also say that "Absence of RCD protection for portable or mobile equipment that may reasonably be expected to be used outdoors" is a C2

Are 'they' correct? Can 'they' say anything 'they' want?

 

[ericmark]

I know a RCD FCU and a RCD socket has the wrong EN BS number to comply with BS 7671, however they are still 10 or 30 mA RCD's and their use would mean a home can pass an EICR even when no RCD fitted in the distribution unit.

Having said that I replaced my fuse box and consumer unit for a new consumer unit with all RCBO's and SPD within first 6 months of moving in. So I would say desirable but not essential.

The fusebox is obsolete, meaning you can keep it exactly as it is if you want, but you can't add any circuits or extend any of the existing ones.

This is a very good point and why I would want to replace the fuse box.

RCDs are a third layer of protection. Newer editions of BS7671 have steadilly increased the number of situations in which they are required, so under current BS7671 most domestic circuits are required to be protected. As an owner occupier you aren't under any legal obligation to update your installation to current standards, but you may find it difficult to find electricians who are prepared to extend a circuit without RCD protection.

In this case looking at the pictures it does seem it is a TN-C-S installation so that is true, I make that point in case some one other than @K-Duffy reads this thread, RCD protection in this case is secondary protection, if it was a TT installation this would not be the case.

When moving into a new home there are 101 things needed money, and you need to work out priorities, I would say waiting a few weeks so enough money to have all RCBO rather than a cheap twin RCD consumer unit is worth while.

I don't know what the 45 amp fused isolator is for? But at moment you have 7 circuits, my house has 14 circuits, so there was a large jump in price for RCBO or twin RCD in my case, but in your case very little in it depends on make used.

So what you need is to decide what you want, if you want SPD or not, and RCD or RCBO, and how many ways, are you likely to fit solar panels or EV charging points in the future, or a garage/shed wanting its own supply or an electric shower?

Not saying now but in the future, as size of consumer unit needs to be selected with future in mind, at least to some extent, I know of people who have done this only to find the make and model of distribution unit was discontinued so best laid plans did not work, but I have work on hold waiting for funds, so well aware of the problem planning what to do with a new home. With my own case waiting to sell old house then all can be done together, but often it is a case of which job first.