Rewiring - Electrics in loft

[ACOperson]

I'm a non-part P gas-fitter, so not great on the lecky regs and need some advice.

Going to get my flat (built 1910 ish, converted in 1979 to 2 flats) re-wired this summer, and I was wondering if the supply cables to the lights (which are run through the loft, currently not clipped or trunked anywhere) will have to be run in conduit?

Also, the consumer unit that is in there at the minute is quite small, and there are only 2 trip switches - lights and sockets. Will this have to be changed or upgraded?

Thanks

 

[JohnD]

It will almost certainly be an advantage to fit a new CU. If you are not on the ground floor, so that an occupier can't be expected to hang a flex out of the window e.g. to mow the lawn or hoover the car, then you aren't required to have an RCD.

However, it is a useful thing to have, for those occasions when you drop the electric kettle in the sink or poke a fork into the toaster (once is enough!)

Two circuits is a bit mean and I am guessing that your old CU is not very modern.

Additionally, you or a future resident may eventually want an electric shower, or cooker, or immersion heater; or have a lot of appliances such as dishwasher, tumble-drier, washing machine, combi microwave, toaster and kettle; if they're all running at the same time (and your fan heaters because the boiler's broken down) then it will be handy to have a separate circuit for the kitchen. My bro-on-law likes to fit an extra circuit supplying the meter cupboard so the owner can have a light on to see what's happened in case the other lights have tripped; and a socket so he can use power tools while the other sockets are off.

By simply fitting a larger CU with room for future expansion, a less costly and neater addition of extra circuits can be done in future. The CU casing is very inexpensive, an empty large one costs little more than an empty small one; most of the cost is in the MCBs/RCD devices.


Clipping cables to joists (above the insulation) is OK; but if you are going to be walking about up there much, mini-trunking is easier than conduit (as you can take the capping off) and will reduce the risk of you tripping or trampling.

 

[Adam_151]

with Twin and earth, conduit is not neceesary unless mechanical protection is needed (metal conduit would be used for this) or its sometimes used in place of capping (to protect against plastering tools, chemical effects of plaster and allow slack to be pulled through)

Cables should be clipped in the loft to provide support, and to stop them getting tripped over, and to make it not look like a dogs dinner

Consumer unit is normally replaced as a matter of course on a re-wire unless there is a good eason not to

 

[ACOperson]

This is the consumer unit we have in at the minute. I don't know if they still make them this small, its just that if we put a new one in we may not be able to fit one which is any larger:

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(its the top one thats ours - upper flat of 2)

Does it look like it needs replacing? I've just noticed the extra trip switch inbetween the lights and sockets, not sure what its for! Will try tripping it tomorow.

Ta

 

[Spark123]

That looks like a 6way board . If you remove the cover (turn off the main switch first), the copper bus bar at the bottom should extend along to where the 6th MCB can be mounted. If you want RCD protection for sockets you can purchase an RCBO with flying lead from Rexel Senate (ask for the Sector GE range). These RCBOs take up two modules in the CU. 16A could be immersion heater?

 

[JohnD]

It's not as old as I'd imagined, looks like a General Electric one (bit confusing, I think the American GE corp, not the old British GEC) and it appears to have room for another 3 MCBs. The tails look clean and shiny, your flat seems to have a better and newer installation than the other flat (though the final circuits wiring might be older than the CU). However it looks as if there ought to be a visor over the MCBs, that is missing. The label was probably attached at installation, is there a date on it that you can read? It looks modern enough that you don't have to replace it, a modern split load might cost £60 or £70 and would include an RCD and more MCBs. Or you could go for RCBOs which I think are superior, if you don't have many protected circuits.

I can't make out the rating of the middle MCB, is it 15A or 16A? if so it could be for an immersion heater (if you have, or had one).

It is also possible that the installer had a spare way in the CU but had run out of blanking plates, so stuffed the MCB in to fill up the gap (!).

To my eye the earth wire looks like a 10mm, not 16mm

edited to say, Spark123 is a faster typist!

 

[JackTheCat]

JohnD
sorry to slightly hijack this post

Is it ok to put spare breakers in CU instead of blanks?

 

[JohnD]

no

 

[Steve]

no

why?

 

[JohnD]

Not connected to anything? Misleading. Confusing. Stupid.


And sloppy workmanship.

 

[PompeySparks]

There is nothing wrong with a spare breaker from a regulatory point of view but I agree with John D...

Blanks are cheap and readily available so there is really no excuse for using circuit breakers although it is still better than a gaping hole!