Rewiring a light fitting without tripping all the electrics?

[coldshoulder]

When I recently set about renewing a light fitting, I isolated the lighting circuit before starting to ensure that there was no live power at the ceiling point.

During the process, the power tripped to the whole house. Apparently, I have been advised since that this was probably because I shorted the neutral and earth wires which remained connected to the main fuse box (and hence the RCD).

This has never happened to me before, so I presume this is a relatively new issue with more modern systems?

My main question is - apart from being really careful to avoid the bare wires shorting - is there any way I can do such a repair without having to switch off the whole housing circuit every time?

 

[Adam_151]

There is, but it involves opening up the consumer unit, which should not be done unless you know exactly what you are doing, as it exposes live parts

 

[ban-all-sheds]

I presume this is a relatively new issue with more modern systems?

That depends on whether you regard RCDs as modern or not.

 

[thomo27]

When I recently set about renewing a light fitting, I isolated the lighting circuit before starting to ensure that there was no live power at the ceiling point.

During the process, the power tripped to the whole house. Apparently, I have been advised since that this was probably because I shorted the neutral and earth wires which remained connected to the main fuse box (and hence the RCD).

This has never happened to me before, so I presume this is a relatively new issue with more modern systems?

My main question is - apart from being really careful to avoid the bare wires shorting - is there any way I can do such a repair without having to switch off the whole housing circuit every time?

I disconnect the CPC's and connector block them , then disconnect the L&N then when ready to connect to the new fitting / socket etc I connect the CPC's first...otherwise as above which invloves opening up the DB...

 

[sparkwright]

I pull the earth sleeving over the ends of the bare earth till I connect them.

Or you could put tape on the ends of the wires till you connect them.

Make sure the wiring is safely isolated though.

 

[xr4x4]

Tell the customer you need to turn all the power off, just turn off the lights mcb, if it trips you did warn them...it's just easier.

 

[coldshoulder]

Thanks guys for all the comments. We may decide to move the consumer unit (which is about 16 years old) from its present location (it is very high and awkwardly located in the kitchen). I was wondering if we changed the unit for a new one if we would still have the same issue, or can they be wired differently to prevent everything tripping?

 

[riveralt]

Thanks guys for all the comments. We may decide to move the consumer unit (which is about 16 years old) from its present location (it is very high and awkwardly located in the kitchen). I was wondering if we changed the unit for a new one if we would still have the same issue, or can they be wired differently to prevent everything tripping?

If you changed the current Consumer Unit which appears to have all circuits protected by a single RCD to a new one, I would suggest that you spend a little bit more and have the consumer unit fitted with a set of RCBO's instead of the standard '17th edition' dual RCD board.
RCBO's control their own circuits and act as a combined RCD and MCB.
With this system if a fault does occur only the circuit with the fault will stop working.

 

[ban-all-sheds]

I was wondering if we changed the unit for a new one if we would still have the same issue, or can they be wired differently to prevent everything tripping?

They can, at some expense.

Is the current behaviour a serious problem for you?

 

[coldshoulder]

riveralt: Thanks for that suggestion - I think for us that is the way forward.

ban-all-sheds: It's not a serious problem but quite annoying when any repairs or modifications are undertaken to have all the lights, computers etc trip off. Anyway, it'll have to wait in the queue until we are a bit less strapped for cash!