A 3 circuit board

[dom2464]

Someone I know who wants a CU change done by me has the old 3036 style board and after I looked at it noticed that it only has 3 circuits for the whole house but really only 2 main circuits and 1 for just 1 plug socket.

1 x 30amp socket circuit

1 x 5amp lighting circuit

1 x 16amp circuit that only runs 1 double socket which is 0.5 meter from the CU.

All this is fed by a 60amp main incoming fuse. The house does not have any known faults but I will be doing a full test on the circuits but they say they have never had a single problem with the wiring ever since the house got rewired in 1984.

I have recomended a board change with RCBO's but I would really prefer a full rewire to break down the circuits into seperate ones.

Anyone every come across a board like this one and changed the CU only to a new one and had any problems with them?

 

[Andy™]

done many similar things before... even installed a 10 way dual split with an entire 2 MCB's in, one each side. it looked kinda empty when i finished, by thats life

 

[dom2464]

done many similar things before... even installed a 10 way dual split with an entire 2 MCB's in, one each side. it looked kinda empty when i finished, by thats life

Hmm 10 way may be a bit over kill me thinks. :^O Think I will stick with a 6 with RCBO's.....B-)

 

[Andy™]

easier sticking with dual split, esp if its TT

 

[NozSpark]

The weird thing about this is that you can get a 10way dual RCD CU for less than you could get a 4way iso CU & 2 x RCBOs...

Even though it would cost a bit more to use a 4way I would never use a 10way for 2 circuits....It'd just look daft!!

Just change the board, if they've been ok with 2 circuits for the last 15 years then I'm sure they will be ok in the future... I guess they have gas C/H and oven

 

[dom2464]

easier sticking with dual split, esp if its TT

Its not a TT its a TN-S system.

 

[dom2464]

Just change the board, if they've been ok with 2 circuits for the last 15 years then I'm sure they will be ok in the future... I guess they have gas C/H and oven

Yeah both are gas.

 

[Andy™]

Its not a TT its a TN-S system.

then no problem with RCBO's

 

[dom2464]

Cheers chaps....B-)

 

[green-hornet]

There are ways to seperate the circuits without doing a full rewire.

I have done loads of this type of work for the electrical safety council grants scheme.

After testing all circuits are sound its easy to find legs in and out, split the circuits and run new legs in to complete a ring or radial.

Lighting circuits are even easier, find the main supply going upstairs, cut it, terminate it, then run a new cable to supply all the upstairs lights.

Longest time I have spent on this type of job was 4 days, and filled a 10 way dual split cu.

Most other jobs of this type was 2 day jobs.

I rewired one house with minimum disruption, and very little redecorating, by use of carefull planning, and speaking with the home owners explaining every step and the outcome of what I would have to do.

It is possible and does not always require a full rewire.

If the tests are ok it does not require a full rewire.

If and only if they are planning any major refurb, then I would reccomend a rewire as a financially sound move.Other than that I never do if the tests are ok.

 

[SPECIAL LOCATION]

As the others have said, If the customer is only asking for a CU change.....

you cannot force or insist upon any reorganising of the circuits.

Providing the the following are all acceptable:-

1/ Earthing & Bonding MUST be sound and electrically safe!

2/ All cables meet suitable insulation resistance values.

3/ Continuity of earths & polarity of live conductors is sound.

4/ All applicable metal accessories are earthed.

5/ Appropriate rating of protective devices are used.

Just go ahead & do it.

If any areas are unsafe.. inform the customer in writing and don't do any further changes until all safety issues can be satisfactorily resolved.

After completing jobs such as this with 1 socket / 1 light circuit, along with the electrical certificate I add an extra observational note that the property would benefit form having additional socket or light circuits to minimise inconvenience in the event of faults.

The only other thing I very often find with these types of in installations is that plastic pendant and rose fittings can be very worn/old/perishing...

So I will suggest replacing ceiling roses/pendants....

But again... the customer has to want it done & be willing to pay!!!!! :|