Electrics Question

Ectophile

stragglebod said:

This is in a house? Are there kids? You need to get that secured immediately. And by 'secured' I mean beyond just locking it.

Is it any different to any other electrical accessory?  If a child gets hold of a screwdriver, they can dismantle pretty much all the electrics in the house.  It's generally considered acceptable if it takes a "tool" to access any live parts.

Mickey666

I'd expect to see some 415V warning signs on a 3-phase system as it's a significant step-up from standard single phase 240v systems in terms of potential danger.

An industrial electrician once told me that it would be unlucky to be killed by a 240Vac shock but would be lucky to survive a 415Vac shock.  I can certainly vouch for the former though fortunately have no experience of the latter!

Risteard

Mickey666 said:

I'd expect to see some 415V warning signs on a 3-phase system as it's a significant step-up from standard single phase 240v systems in terms of potential danger.

An industrial electrician once told me that it would be unlucky to be killed by a 240Vac shock but would be lucky to survive a 415Vac shock.  I can certainly vouch for the former though fortunately have no experience of the latter!

There is no need for a 400V (not 415V - the harmonised voltage is 400/230V) warning as the voltage to Earth does not exceed 230V.

FreeBear

Mickey666 said: An industrial electrician once told me that it would be unlucky to be killed by a 240Vac shock but would be lucky to survive a 415Vac shock.  I can certainly vouch for the former though fortunately have no experience of the latter!

I have experienced both. 240V just buzzes. 415V, all three phases darned well hurts - Can't use the words I'd like to...

Risteard

FreeBear said:

Mickey666 said: An industrial electrician once told me that it would be unlucky to be killed by a 240Vac shock but would be lucky to survive a 415Vac shock.  I can certainly vouch for the former though fortunately have no experience of the latter!

I have experienced both. 240V just buzzes. 415V, all three phases darned well hurts - Can't use the words I'd like to...

It's pretty unlikely that you simultaneously came into contact with more than one phase. If so, how did it happen? (And you are incredibly lucky to be alive.)

shinytop

An electrician was in attendance so I asked.  He agreed with @Ectophile; it's a 3 phase supply and the switch in the box is a contactor.  It switches over at Economy 7 on/off time.   I think the yellow and black hazard tape conveys the extra danger of the additional voltage quite well, as well as brightening up the utility room.   BTW it is, and always has been, a dwelling house with no additional electrical machinery. It does have a lot of night storage heaters and a 30 Amp Aga so maybe that explains it.  Apparently 3 phase supplies were put in houses reasonably often a while ago; less so now. 

Thanks to all who replied.  

Risteard

shinytop said:

I think the yellow and black hazard tape conveys the extra danger of the additional voltage quite well, as well as brightening up the utility room.

Not what it's there for. It's because the phase colours used to be red (L1); yellow (L2); blue (L3) and black (N).

This has since changed to brown (L1); black (L2); grey (L3) and blue (N).

In Ireland in between these two sets of colours at one time was brown (L1); red (L2); yellow (L3) and blue (N).

Whilst domestic three-phase supplies are common on the continent, they have never been usual in Britain or Ireland. Very occasionally a large house might have one. Instead we tend to use larger single phase supplies, with typically commercial and industrial etc. installations on a three-phase supply.

grumbler

Risteard said:

Not what it's there for. It's because the phase colours used to be red (L1); yellow (L2); blue (L3) and black (N).

That was about the first photo, not the second  - the tape around the box.

shinytop

grumbler said:

Risteard said:

Not what it's there for. It's because the phase colours used to be red (L1); yellow (L2); blue (L3) and black (N).

That was about the first photo, not the second  - the tape around the box.

Yes it was, Mrs S put it there as a bit of a laugh.  Obviously being very careful not to touch anything whilst doing it.