help with regs.

[danny7299]

Hi there , went to do a PIR today, only done a few so for.

it was in a big work shop, and there wasn't any bonding to the Gas.

there was a 400A supply, in 185mm 4core SWA.

the gas was a run about 100 meters .

my questions are...

1) Reg 544.1.1 , i think it is saying that max main bonding need not exceed 25mm, but then table 54.8 seems to say otherwise...

2) i am still trying to understand the language of the regs... any one got any tips to understanding them, headbang

cheers all

 

[Zeespark]

The adiabatic equation will help Danny.

AndyGuiness Drink

 

[danny7299]

got it... reg543.1.3

 

[danny7299]

isn't that for a protective conductor and not a bonding conductor? hummm...

 

[danny7299]

let me see if i have got this right...

got a main incomer of 400A going to bus bars, from the bus bars , it goes to 3 boards.

i got Zs at the boards i got 0.23 and a PFC of 1.1kA give or take from all 3 boards, ( they are next to each other)

when working out the bonding, do you use the information above or do i need to test the 400A supply and work out from that?

got my self a little confused so any help would be great!/

 

[danny7299]

well after not much help... went an bought the IEE earthing and bonding book today...

and it states that for a 185mm supply with a 95 mm earth a 25mm main bonding conductor is needed.

Main equipotenteial bonding need not exeed 25mm.

 

[Apache]

Danny you appear to be talking to yourself............

 

[Andy™]

Danny you appear to be talking to yourself............

have you been removing your posts?!

 

[Apache]

[quote name='Andy

 

[Andy™]

you manage to do that without removing your posts!

 

[Apache]

[quote name='Andy

 

[spinlondon]

The 25mm

 

[danny7299]

yes you are right on both counts...

i was talking to my self and 50mm is the max for a TNCS supply.

 

[danny7299]

so then just filling out forms ...

400 Amp supply feeding bus bars, which then feeds 4 DB. All boards are fed in 50mm SWA.

I prosume that the bonding size is taken from the 400A as this is the Supply...? and not the size of the boards (50mm)