Isolated the kitchen sockets but bang

[bizron]

Confused- I isolated the kitchen sockets by flicking the RCD trip to the kitchen sockets then went to cut the 2.5mm cable in the kitchen and the house lights lights tripped. What's going on? Do I need to turn off at main switch in order to add new cable and sockets?

The house is on 4 rings (?) downstairs sockets (RCD protected), Kitchen sockets, upstairs sockets and lighting (RCD protected)

 

[PrenticeBoyofDerry]

Did it go bang, or did the RCD trip? shorting between neutral and earth will trip the RCD even if the MCBs are open circuit.
If you want to extend circuit, without tripping the RCD, you will need to isolate at MCB then remove neutral/neutrals of circuit from the neutral busbar, or every time you touch neutral and earth the RCD will trip.

 

[bizron]

Did it go bang, or did the RCD trip? shorting between neutral and earth will trip the RCD even if the MCBs are open circuit.
If you want to extend circuit, without tripping the RCD, you will need to isolate at MCB then remove neutral/neutrals of circuit from the neutral busbar, or every time you touch neutral and earth the RCD will trip.

Cheers PBD super speedy reply too. No it didn't bang but the RCD did trip just wanted to get attention with the bang. So I shorted the circuit right got you,... no danger with live wires then?

 

[Taylortwocities]

There is danger until you sort out your terminology.

Confused- I isolated the kitchen sockets by flicking the RCD trip to the kitchen sockets

I think you mean MCB, not RCD? The RCD has a test button.

I hope you used a test meter to make sure that power IS disconnected.
I have been to too many houses where if you switch off the MCB marked kitchen sockets, its switches SOME sockets off, but others are live as they are add-ons from somewhere else.

Always, always test for live, switch off, then check it really is dead. Also prove your test meter before and after.

 

[WabbitPoo]

If you short across the L and E, or across the N and E, your RCD will trip.

It makes you jump, doesn't it?!?

Please ensure you test for dead as above...

 

[EFLImpudence]

If you short across the L and E ... ... your RCD will trip.

Not if the advice below has been followed.

Please ensure you test for dead as above...

If the advice has not been followed - BANG as well.

 

[ericmark]

There is a difference between isolation and switching off. To isolate you need to open ALL live connections to switch off you only open line connection. Neutral is classed as a live wire.

551.6.2 For a TN-S system where the neutral is not isolated. any RCD shall be positioned to avoid incorrect operation due to the existence of any parallel neutral-earth path.
NOTE: It may be desirable in a TN system to disconnect the neural of the installation from the neutral or PEN of the system for distribution of electricity to the public to avoid disturbances such as induced voltage surges caused by lightning

559.10.6.1 Where it is intended that isolation and switching is carried out only by instructed persons and subject to suitable provisions being made so that precautions can be taken to prevent any equipment from being inadvertently or unintentionally energized, for TN systems, the means of switching the supply on load and the means of isolation is permitted to be provided by a suitably rated fuse carrier.

In other words if you have the skill required you can work with the neutral live but for DIY you need to switch and lock off the isolator not just a single pole RCBO or MCB isolators will always be two pole or more.

 

[bizron]

If you short across the L and E ... ... your RCD will trip.

Not if the advice below has been followed.

Please ensure you test for dead as above...

If the advice has not been followed - BANG as well.

If I am wearing rubber soled shoes rubber knee pad and rubber gloves can I touch the live to see what it feels like?

 

[PrenticeBoyofDerry]

If I am wearing rubber soled shoes rubber knee pad and rubber gloves can I touch the live to see what it feels like?

Oh course you can, crack on it's your life!
PS. Am I in your will?

 

[WabbitPoo]

If you short across the L and E ... ... your RCD will trip.

Not if the advice below has been followed.

Please ensure you test for dead as above...

If the advice has not been followed - BANG as well.

I meant, the RCD goes click/bang (depending on how echoey its cupboard is!). If, as in my case, the lights go out too, then it does indeed make me jump!

 

[aesmith]

If I am wearing rubber soled shoes rubber knee pad and rubber gloves can I touch the live to see what it feels like?

No. Even if that was a joke.