feed to DB has earth through a seperate bush to L&N????????

[Sidewinder]

That is the gist of it App87.

 

[kme]

The point I made earlier mate, was that the enclosure in question is physically & electrically connected to the trunking through which the cables are travelling; ergo they`re already surrounded by an earthed enclosure. Now d`you get my point?

 

[Sidewinder]

Yes, however, you are still penetrating a ferrous plate whilst entering the db from the trunking so you will still get the eddy current phenomenon.

 

[kme]

Accepted - I wasn`t referring to it negating eddy current issues bud - I was looking for a way of explaining compliance with 521.5.2

 

[philbas]

I dont think eddy been in the time contineuem is disputed

My point is that if you have to consider him you already have a much bigger problem to contend with, Vogans on the starboard bow maybe

To elaborate we are protecting against something that can't happen with out a much bigger problem elsewhere

 

[Sidewinder]

Things is AFAIK that reg is only related to eddy currents.

 

[philbas]

If it was L-N I would tend to agree, although I still can't find a case of Eddy causing problems, i think this is another case of scacremongering.

But in this case we are talking cpc.

If you have enough current in the cpc for eddy to be a worry then the rest of the place is going to be in flames.

 

[Sidewinder]

Still a reg though mate!

There are many regs I don't agree with, but they are regs none the less.

 

[philbas]

Not disputing that, they just throw in terms like "ferromagnetic enclosure" without defining them.

At the end of the day the qustion should allways be "Is it safe"

In terms of the OP I think it is, you may chose to differ

 

[Bacon]

Was on a job recently new warehouse for B&Q in Swindon and every SWA had a seperate earth connected to it be a dist board or isolator.

 

[apprentice87]

Hi all,

More newbie neck sticking out here!!!

"Was on a job recently new warehouse for B&Q in Swindon and every SWA had a seperate earth connected to it be a dist board or isolator"

Presumably it was done to lower Zs on long runs, or could it have been perhaps, intended not to be a CPC as such, or at least not purely as a CPC, but instead to have the intended primary purpose to act as the required size bonding conductor for PME perhaps???

john...

 

[Badger]

i was wondering if an insulated c/u made from plastic non ferrous :slap

 

[steptoe]

I dont see the earth as entering the enclosure, it is a part of it,

now, if it was coming from PVC trunking into a metal enclosure then I could understand the issue,

but, the trunking is metal, thus part of the earthing circuit, the enclosure is metal, so therefore also part of the earthing circuit,

the CPC is terminated in the enclosure, so therefore also part of the enclosure and the trunking earthing circuit.

so it is not entering the enclosure, it is a part of the enclosure....

making sense to anyone but me? :|

 

[NozSpark]

I dont see the earth as entering the enclosure, it is a part of it,now, if it was coming from PVC trunking into a metal enclosure then I could understand the issue,

but, the trunking is metal, thus part of the earthing circuit, the enclosure is metal, so therefore also part of the earthing circuit,

the CPC is terminated in the enclosure, so therefore also part of the enclosure and the trunking earthing circuit.

so it is not entering the enclosure, it is a part of the enclosure....

making sense to anyone but me? :|

I see where you're coming from,,,,, but would the trunking be part of the earth fault path?? Possibly not

 

[SLIPSHOD & SLAPDASH]

Hi ppl,A DB sitting on metal trunking, it's 25mm bush/lock ringed on the trunking,

Brass bush

 

[batty]

know his brother george.

 

[SLIPSHOD & SLAPDASH]

know his brother george.

Micheal ?

 

[batty]

thats his cousin.

 

[SLIPSHOD & SLAPDASH]

My mistake

 

[batty]

Don't forget his sister Kate i do love her music.