Diff Phase Circuits _ How far apart

[Fratton sPark]

Hi All, can someone please jog the cobwebs from my memory.
When installing single phase circuits fed from different phases, how far apart should fittings etc. be? Its been a very long time since I needed to worry bout this, cause most of my circuits on different phases are always a substantial distance apart (if that makes sense)?
But yesterday at work, my workmate installed a socket (on black) about a foot away from light switch (on brown), (don't ask why, cause I don't know how his head works lol).
But when trying to explain to him what was wrong, for the life of me I couldn't quote a distance/ reg.
If someone could please jog the old grey matter (my brain, not the other phase) would be very much appreciated.
TIA Fratton sPark.

 

[fattony]

Hmm i cant quite remember the reg but its down to the potential between the 2 phases under fault conditions. I believe you can have for example sockets next to each other on different phases but you must put a sticker on each socket stating the potential of 415v

Someone will correct me if im wrong

 

[Steve]

i've seen light switches with warning stickers between. It was in the electrical cabinet of a large convenience store. had a large grid of light switches (probably different phases in same grid) and heater controls and a couple of sockets.

 

[jondiy]

Correct me if I'm wrong, but I think its either 2 or 2.5 metres. You can have accessories on different phases within that distance , but you have to display the 400v warning on both accessories.

Although it's not ideally practiceable to put them as close as that, afer all, two lives (on different phases) within arms reach can give rise to 400v of shock

 

[PompeySparks]

As a rule of thumb, I like to keep different phases to different rooms (if possible)

If in close proximity then correct labels cover you in any instance (even two phases in the same gridswitch etc)

 

[RF Lighting]

While doing some work in a factory canteen the other day, I came across a socket and FCU on diferent phases within 50mm of each other. No warnings. Nothing. Should have had one of these attractive beautys Click Here. As crafty said it is ok to have mixed phases within the same gridswitch aslong as warnings are displayed. (MK supply the stickers with their grid frames). I seem to remember reading somewhere that the 15th edition of the regs used to call for seperation between different phases (not sure of the distance) but this is no longer the case. (providing warnings are displayed)

 

[fattony]

As a rule of thumb, I like to keep different phases to different rooms (if possible)

Bit tricky when you have fluorescent loads and moving machinery the lights are supposed to be on different phases, guess you did cover yourself by saying if possible.

 

[PompeySparks]

Yep I know there are always exceptions!



Lighting is a different matter and as you say, it is good practice to split flourescents across the three phases when moving machinery is involved!

It's because a motor and a flourie on one phase can reach similar rates of rotation/flicker making the machinery look like it is stood still!

Spread your flourescents across the phases and the flicker rate is three times as high - giving much clearer vision!

I didn't say so in my post but my separate rooms comment was referring to sockets only!

 

[Fratton sPark]

Thanks guys, totally agree bout the sticker issue. Also, cheers Jon, thats what I seemed to remember. Out of arms reach, or around 2-2.5m if no stickers.
just wish I could see something in print, as a benchmark, so to speak. I'm guilty of being a bit of a stickler (not sticker) for details

 

[jondiy]

It is in the 16th regs, I stumbled across it the other day, it was near to the section which describes high CPC currents whereby you needed the cream cloured sticker to display the prescence of those High CPC currents.

Could be near the end of Section 6, when I get 5 mins, will point it out to you.

 

[Jaymack]

This is probably what you are looking for.
461-01-03 Where an item of equipment or enclosure contains live parts that are not capable of being isolated by a single device, a durable warning notice shall be permanently fixed in such a position that any person before gaining access to live parts will be warned of the need to use the appropriate isolating devices, unless an interlocking arrangement is provided so that all the circuits concerned are isolated before access is gained.

514-10-01 Every item of equipment or enclosure within which a nominal voltage (UO) exceeding 230 volts 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.

Where terminals or other fixed live parts between which a nominal voltage (UO) exceeding 230 volts exists are housed in separate enclosures or items of equipment, which although separated, can be reached simultaneously by a person, a notice shall be secured in a position such that anyone, before gaining access to such live parts, is warned of the maximum voltage which exists between those parts.

Means of access to all live parts of switchgear and other fixed live parts where different nominal voltages exist shall be marked to indicate the voltages present.

Jaymack