electic shock conditions

[archie]

theoretical question this,is it possible to get a serious shock when working on neutral conductors when live has been switched off,if so how does this arise [when working local lighting circuit for example with wall switch off but double pole mains still on ] not that I would engage in such practice but I need to know how the danger exists to understand it.talking about uk domestic mains supply
thanks-archie-

 

[ZenStalinist]

What version of electricity are you using? I find 3.1 is terrible, but not as bad as 98.

 

[Igorian]

Not to mention part SP2!

 

[breezer]

he really wants eXtra Power professional

 

[felix]

You're on the wrong forum but I'll answer anyway. Consider this scenario.

You turn off the light switch but other lights are still on and their neutral returns are in the junction box you're working on. Now, carefully, remove the neutral wire that goes back to the consumer unit. You will be greeted by a modest amount of sparking and all the other lights will go out. Congratulations - you now have a lot of live neutral wires in there.

Pulling the fuse is better but still not 100% safe, especially with lighting circuits. I once found a two way lighting circuit in which somebody had cut a lot of corners. For a start, all the earths were twisted together outside the junction boxes but the main problem was with the switch wiring. Some penny pinching dipstick had taken live power from the upstairs lights down through the two way switches to the downstairs hall light. This wouldn't have been so bad but the neutral return was to the downstairs circuit.

The answer to your question is this. A neutral terminal should be safe only while it is still connected back to the consumer unit. Once you start taking wires out, all bets are off.

 

[kendor]

Congratulations - you now have a lot of live neutral wires in there.

I understand what you are saying but on a technical point the neutrals cease to be that once disconnected they are only neutral whilst connected to a neutral supply terminal when disconnected they are now live, albeit with resistance in series but nonetheless live

a serious issue especially with multi phase distboards is when the neutral bar becomes disconnected from the supply neutral for whatever reason and the circuits still connected together via the now live bar can actually end up across two phases! with rapid failure ensuing afterwards, i've been witness to this happening in the past.

 

[2scoops0406]

And the original post is 3 months out of date.

 

[pipme]

.......... A neutral terminal should be safe only while it is still connected back to the consumer unit. Once you start taking wires out, all bets are off.

Hugely important, and should make us amateurs stop and reflect upon just how much there is to think about ...... Simple couple of sentences but conveying much about the oft quoted, but not explained 'borrowed neutral' scenario. Oops ! there is a drawing and explanation by BAS here //www.diynot.com/forums/viewtopic.php?t=7553&start=31
Nice one(s) !!!
And you Dorken, not forgotten !!