Discuss 3 phase db converted to single phase with 10mm earth in the Electrical Forum area at ElectriciansForums.net

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daveelectrician

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Hi.Today during my job at a police station, took cover off brand new KQ 3 phase SquareD db (recent db change by different firm) to connect my new ring to one of the ways and found that the 3 phase db had been converted to single phase. 25mm double insulated tails live and neutral, L1, L2 and L3 linked out using some 10mm earth cable. To me i would say that is a c1 fault, so refused to make my circuit live until c1 was rectified. What is everyones opinion on this and does anyone know if there is a linking kit available from schneider.
 

DNS1

Electrician's Arms
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If all 3 phases are connected together and to the line side of the incommer, surely that means 415v for the whole system?!

I'm not an expert in 3 phase, but that just sounds plain wrong (and that's before we get to using 10mm earth as a line conductor!)
 
K

Knobhead

Have you been in touch with Schneider?

It's not unusual to convert a board like this. One danger is the neutral rail being overloaded.
 
K

Knobhead

If all 3 phases are connected together and to the line side of the incommer, surely that means 415v for the whole system?!

I'm not an expert in 3 phase, but that just sounds plain wrong (and that's before we get to using 10mm earth as a line conductor!)
How do you work that out?
 

Amp David

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Some manufacturers do sell a conversion kit that does exactly what you have found
 
G

Guest123

Single phase conversion kits are available when using a 3p DB with a 1p supply.

Linking out using 10mm is dog rough but not a C1 imo.

Sent from my HTC Desire C using Tapatalk 2
 

Richard

Regular EF Member
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If all 3 phases are connected together and to the line side of the incommer, surely that means 415v for the whole system?!

I'm not an expert in 3 phase, but that just sounds plain wrong (and that's before we get to using 10mm earth as a line conductor!)

No I think the Op means that it's a three dis board fed by a single phase and neutral...no?
 

DNS1

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No I think the Op means that it's a three dis board fed by a single phase and neutral...no?
Oh, ok, that makes more sense... It sounded like he was talking about a single phase board being fed by all 3 phases!

My bad!

:blush5:

I really shouldn't use this forum after beer...
 

Rob

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Deleted (cos I was being stupid!)
This is true, but it sounds like a 3ph dis board which has been converted to single phase.

The supply to it will be single phase line, neutral all that's been changed in the board is the 3 bus bars internal to the db have been linked together, albeit roughly.
 
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daveelectrician

EF Member
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Thanks everyone for your replies. Will ring schneider tomorrow to see if there is a linking kit. Thought it was a C1 as 10mm not rated 100 A
 

Rob

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The boards rated at 100a across three phases. What protection is on the supply cable?
 
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daveelectrician

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100amp BS88 2X 25mm (live/neutral) tails into 4 pole tpn 60947-3. 25mm live in L1 terminal, linked to L2+ L3 with 10mm earth cable. 8 way tp board 1 tp way spare.
 

Adam

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When fitting, make sure to fit as per picture on link. They come with no instructions.
I fitted one last weekend, as I had a similar issue that was a defect on EICR. Mine was slightly worse, as they were linked with 6mm2 singles.

I have seen these linking kits installed under the main switch, which is not a good idea as you have a nice shiny piece of live metal when cover is removed.

The linking kit sits nicely on existing bus bars, and the main switch then holds it in place.
 

snowhead

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When fitting, make sure to fit as per picture on link. They come with no instructions.
I fitted one last weekend, as I had a similar issue that was a defect on EICR. Mine was slightly worse, as they were linked with 6mm2 singles.

I have seen these linking kits installed under the main switch, which is not a good idea as you have a nice shiny piece of live metal when cover is removed.

The linking kit sits nicely on existing bus bars, and the main switch then holds it in place.
Do the kits come with blanking plugs for unused terminals, otherwise they would be left exposed live, if anyone was stupid enough to stick thier finger in?
 

Adam

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Do the kits come with blanking plugs for unused terminals, otherwise they would be left exposed live, if anyone was stupid enough to stick thier finger in?
Nope.

You get the shorting bar only. Tighten the spare terminals all the way, then there is less chance of touching the live terminals. You would have to really try to get a shock off it.

Anyway, I know you would isolate the DB before removing the cover, so the spare terminals would not be live as they are linked on load side of switch.
 
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