inspection and testing

[Engineer54]

evening all,
I am carrying an inspection and test of a board which is located in an area similar to a swimming pool - the board is 40 years old - has no main earth and is reliant on the the conduits connection for earthing- there is no MET within board - all earths are connected to board chassis - there is no rcd protection. The environment is a harsh corrosive environment - some ZS values are high on certain circiuits what is the minimum I can do to get this board to a satisfactory state so that it would pass an EICR.

Cheers

I think you've had the answers to the more relevant of your questions. The installation sounds as if it's been installed to a pretty high standard for it's day, and as others have stated the conduit IS the CPC, and as the whole installation is metal conduit containment you won't see any separate CPC's unless the board has been added too, with installations that are not in metal conduit containment.

What do you mean by a ''harsh corrosive environment'' and what damage has it caused to this installation?? What do you mean by high Zs values, (you have been asked that a couple of times already but still no feedback)?? What's the Zdb at this fuse board and at the isolator switch below the fuse board?

The older metal fuse boards/isolators etc, didn't come with a means of connecting CPC's as there were none. At the origin of this installation is about the only place you'd actually see a main earthing conductor, and then the chances are it would be a bare conductor connecting to the installations main switch fuse.

The main problem i can see with this sub main, is if any service pipework or structural steel needs main bonding, only you will know the answer to that question. It could well be that all main bonding has been carried out for this building and connected to whatever is being used as the installations MET at the origin of the installation... It may be prudent to check if the sizing of those main bonding conductors are compliant, remembering that they may well be Imperial conductors

On a final note, i personally know of full galv' metal conduit containment systems that haven't been mucked about with, that have been in place 60+ years. The only work that has been carried out on them, being replacing the old VIR wiring and updated fuse boards some 35/40 years ago and not a single CPC conductor to be seen in any of the conduits. I can guarantee that those installations will still be giving Zdb/ Zs values that would impress even the most sceptical among us!!

 

[Knobhead]

listen guys input would be welcome Thanks

I was just suggesting it's 40+ years old and updating it to something modern wouldn't go a miss. I'm sure it works perfectly well, but it would be nice to update it.

£X000 just because you think it would be “nice” to upgrade it?

Get real!

 

[nickblake]

I just cant understand why people get so worked up when steel conduit is used as an earth and no separate earth if you work out the cross sectional earth of a conduit and compare that to say a 1.5 or 2.5 earth or even greater size, there will be no comparison, as long as the conduit is good and sound condition then there's not a problem

 

[baldsparkies]

I just cant understand why people get so worked up when steel conduit is used as an earth and no separate earth if you work out the cross sectional earth of a conduit and compare that to say a 1.5 or 2.5 earth or even greater size, there will be no comparison, as long as the conduit is good and sound condition then there's not a problem

Because they lack a general understanding, knowledge or experience.
Nothing more. Nothing less.:icon12: