Temporary cabin

[Stocksie]

I've been asked to supply a temporary cabin on a warehouse site.

The garage that services the trucks has a Square D D.B. (used as a Section Board) which feeds 3 other D.B.s in the garage, one 3 phase , one 110v and one single phase. All pulling no great load.

The supply to this sectin Board is from the Mains Shed where there is a Merlin Gerin S.B. and a 250 A MCCB which feeds the Garage Section Board via a 50 mm2 XPLE cable which is on rack ,tray and duct (duct for most of it's length)

The Zdb at the garage section board is 0.41 ohms !

I've used the cable mate site and and this does not comply as far as I can see.

There is no seperate earth conductor run with this XPLE SWA.

A large contractor installed this and I'd have expected it to be done correctly, or am I missing something?

From my understanding theMCCB is way oversized and will not meet disconnection times ( I think most prob as is was existing in the section board (premesis had a prior use ))

And the cable is undersized ( I get it at 90mm2)

There is no bonding directly at the garage Section Board but at one of the sub boards to gas,water and steel.

Therefore am I correct in saying I can not supply the temporary cabin from the Garage S.B. unless something is done about it's supply cable and/or MCCB ?

Many Thanks

 

[Stocksie]

Forgot...T.N.S supply

 

[Guest123]

Is the MCCB not adjustable I.e, is it turned down to a lower current than its maximum rating?

Sent from my HTC Desire C using Tapatalk 2

 

[huddsy]

Shed
is a temporary cabin so shouldn't it be on a TT as its a special location ??

 

[Stocksie]

Huddsy - Mains shed as in Mains room/boiler house etc. Its a stell building .

Lenny - Yeah i'ts turned down to 0.7 but thats still 175 A.

I spoke to NICEIC Tech today, explained the scenario, he took some figures off me and said it would be ok if it could be turned down to 50%... but it can't.

I found a Merlin Gerin 160 A MCCB on the premesis, I'll fit this although it needs a steel mounting plateas it is physically smaller.

I still say the cable is undersized though. We got the measuring wheel on it today and it's 140 m !

I cant get my calcs anywhere near it being acceptable using the cable mate program.

It was on of thebig outfits in the North East that installed it to.