This could be a daft, or really important question...

[Eddiesparks]

If you had a 3ph dist board and for example in the kitchen there was a dishwasher on 1 phase and the sockets on another, and their exposed conductive parts were within reach of each other must this be considered in case someone touches both in fault conditions and gets 400v up one arm and down the other or is it deemed such a small risk that you dont worry about it.

Like I said it may be a really stoopid question but I dont know the answer. Happy to look up in regs book but i think to find it (or not) it may take all night.

Thanks boys and girls

 

[jackhammerJIM]

You are correct Eddie , It is really daft

 

[Des 56]

You are correct Eddie , It is really daft

That was short and too the point jack

 

[SirKit Breaker]

Both circuits should be suitably earthed, and in your scenario RCD protected, so in theory it should not happen, but you are right the potential for 400v exists, and it probably is such a low risk anyway, that it isn't worth considering as this is probably very common in commercial/industrial installs. However i am not saying that i am right.

I would give the regs a miss mate, there are far more interesting things to read at this time of night.

Cheers…………..Howard

 

[Eddiesparks]

Hey at least i am considering possible safety issues instead of just installing stuff that could be lethal without thinking haha!!

 

[tazz]

Very common on industrial lighting, where one or two phases are common in the grid switching.....BS answer is to clearly mark the switches or outlets, that 400v maybe present..

 

[jackhammerJIM]

Can never be too careful these days Eddie . :death:

 

[Darkwood]

230v kills... 400v kills when you exceed SELV you are at risk the current flow will kill you if not cause internal injury ... with higher voltages this does increase the current flow but again at mains voltage be it L/E or L/L its down to circumstances and chance as they both should be treated with the same respect.

 

[uksparks]

I would probably advise putting 400v between stickers where appropriate to indicate to whoever next carries out work.

 

[Rockingit]

You go sticking 400V warning stickers on sockets in a kitchen and all you'll end up with is some very worried and confused people surrounded by an awful lot of cold food.

In a properly protected installation it's just not an issue - as DW said, anything over SELV is equally as lethal! And I say that as someone who's taken 400V belts, too.

 

[Eddiesparks]

230v kills... 400v kills when you exceed SELV you are at risk the current flow will kill you if not cause internal injury ... with higher voltages this does increase the current flow but again at mains voltage be it L/E or L/L its down to circumstances and chance as they both should be treated with the same respect.

230 can and does kill but we've all had a few and live to tell the tale! Just goes to show the importance of voltmeter and proving unit!

Customers are always amazed if you say you've had a few shocks.

What is confusing is you can get a little jolt off something that is on an rcd and the rcd never trips. Pullaway reactions must be quicker than the rcd which is pretty damn quick!!

 

[uksparks]

What is confusing is you can get a little jolt off something that is on an rcd and the rcd never trips. Pullaway reactions must be quicker than the rcd which is pretty damn quick!!

I stupidly got a belt in my own house from the end of a bit of 1.5mm that I'd just fed through the ceiling and then thought yep that's all done and forgot to put a switch on the end, turned it on caught the back of my hand on it and zapppp, I bloody felt it, but didn't trip the RCD.

 

[uksparks]

You go sticking 400V warning stickers on sockets in a kitchen and all you'll end up with is some very worried and confused people surrounded by an awful lot of cold food.

In a properly protected installation it's just not an issue - as DW said, anything over SELV is equally as lethal! And I say that as someone who's taken 400V belts, too.

I agree with that, but would you not say that you are not complying with the regs by failing to warn people of the voltage? I'm in bed and regs book is downstairs so don't know exactly what it says, but I was under the impression that you should be making it clear that you have a 400v potential.

 

[Lucien Nunes]

There's no point putting 400V stickers where the 400V isn't accessible. In your scenario, one phase is no more accessible from inside the dishwasher than it is within the wiring system, and you wouldn't go sticking 400V stickers all the way along the trunking. The main point of the stickers is to warn of the presence of a voltage where you wouldn't expect it, e.g. when two phases are contained within single-phase equipment.

Too many stickers defeats their purpose - to warn of a significant hazard. It's crying wolf to stick them everywhere, especially when as mentioned above the system users won't understand their significance. If they see a 400V sticker, they may imagine the socket itself supplies 400V and refuse to use it. I have seen precisely this result occur.

 

[Darkwood]

230 can and does kill but we've all had a few and live to tell the tale! Just goes to show the importance of voltmeter and proving unit!

Customers are always amazed if you say you've had a few shocks.

What is confusing is you can get a little jolt off something that is on an rcd and the rcd never trips. Pullaway reactions must be quicker than the rcd which is pretty damn quick!!

Don't forget the voltage can make the muscles spasm extremely fast and this can equate to the sense on a big shock that should have tripped an RCD ... your body resistance plus footware etc can limit the current flow and thus you get what seems a heavy shock but in fact very little current flowed..

Measure you body resistance and work out what 230v will push through you too many factors apply to give an average figure for body resistance but last time i measured mine between my hands it was about 25,000ohms...the thing about electric is the consequence of it flowing through your body can be to lower the resistance you had against it as it breaks down the skin barrier so unless power is cut or you are released from its grip things can quickly go downhill as current flow rises.

 

[D Skelton]

Very common on industrial lighting, where one or two phases are common in the grid switching.....BS answer is to clearly mark the switches or outlets, that 400v maybe present..

Not quite right, I got corrected on this a short while back and made myself sick on heaps of humble pie!

You only need to label when a nominal voltage higher than 230V to earth exists. Apparently the regs have changed and what you said was previously included, but now isn't

 

[old_sparky_RE]

From the BGB 514.10.1:Every item of equipment or enclosure within which a nominal voltage exceeding 230 volts to earth exists and where the presence of such a voltage would not normally be expected, shall be so arranged that before access is gained to a live part, a warning of the maximum voltage present is clearly visible.
230V to earth - no mention between phases. GN1 pg 25 also covers this.

So no labels required under 17th Edition

 

[telectrix]

Field marshall Rommel beat us to it. absolutely correct. the electrical world has gone sticker crazy. next thing is showers and kettles will be stickered up with "WARNING, HOT WATER". FFS.

 

[R G]

A big notice at the front door on the outside wall , 4 ft square could cover the whole house , a disclaimer for every single thing in the house , mine says beware of the wife as well , dogs all right mind you , those door mats are good as well,, lol..

 

[dazza1981]

Field marshall Rommel beat us to it. absolutely correct. the electrical world has gone sticker crazy. next thing is showers and kettles will be stickered up with "WARNING, HOT WATER". FFS.

Tel are you saying you dont want pat testing stickers slapped all over your nice new 50 inch tv lol