EICR

[cliffed]

Doing an eicr on transport company's yard,most probably 15 years+, old.
Normal observations,wondering what you guys think about this one,in the middle of nowhere there are 3p/N/E commando plug/ sockets,rated 32amps,these are used for charging refrigerator units,supplied with trailing leads.
They are cabled undergrd by swa cabling,to a 4 pole rccd 30 ma,this is from a DB 32amp 3p MCb.using the sheath as earth & PME From the DB For its earth ,anyone see any probs.

 

[telectrix]

what regulation do you think it contravenes? and what's the csa of the swa?

 

[cliffed]

what regulation do you think it contravenes? and what's the csa of the swa?

Swa is 6.00mm so everything ok there,basically main earth for the circuit,& maybe the earth system,should it be tt

 

[cliffed]

Worried about pme at the rccd position,should it be to at that point

 

[cliffed]

Sorry image loaded too many times

 

[telectrix]

i see your point, as that installation is similar to car charging points in that you are charging equipment on metal vehicles. i'd be glad to hear the views of other members on this one.

 

[westward10]

I don't see a problem, the power to these trucks is not for use as a habitable environment. I have tested many a site with the same set up and made no comment.

 

[Richard Burns]

I would have said that the potential for a risk is present, however the power supply for the refrigeration unit should be entirely insulated from the vehicle wiring and so the chance of there being an exposed conductive part of the 3 phase installation that is accessible to touch when charging the units would seem to be very small.
Ideally a TT earthing system could be employed effectively here but a risk assessment may well conclude that it is not required to reduce the risk of perceived shock.
However you have seen the installation and would be best placed to make that judgement.

 

[cliffed]

Thanks,it's been like that when originally installed,bit of a nightmare to actually TT the system,but will note my concerns.
I'm afraid it's the same old installation problems we find,leaving it as it was.
Swa's installed & using the sheath for both earth & main bonding,& near impossible to correct now,but for my conscience I will note,& then up to my superiors to decide.

 

[Wilko]

Oh dear, if bonding is wrong too I would like to see that addressed before any further work. Is that being too harsh?

 

[westward10]

Oh dear, if bonding is wrong too I would like to see that addressed before any further work. Is that being too harsh?

I would say bonding is an issue but the sockets in my opinion are not, God damn TN-C-S.

 

[cliffed]

Oh dear, if bonding is wrong too I would like to see that addressed before any further work. Is that being too harsh?

No ,that's my opinion to,just noting what's gone wrong over a period of years,& see what happens.
I really can't see any change in the installation happening though,cabling all underground & a long way away from main intake.Thanks anyway.

 

[cliffed]

I would say bonding is an issue but the sockets in my opinion are not, God damn TN-C-S.

Agree,thanks

 

[cliffed]

What's your views on,while doing this report,finding swa's are being used for main & bonding conductors.A sub main from intake cabinet,on a tncs system,35mm 4 core swa to a TPN DB.
The swa is connected to the Db,& a link from banjo to the MET.
A earth conductor then connected to a structural steel frame building,then another to a water pipe etc.
To use this earthing system,a bonding conductor sized correctly should be used.
Near impossible to get this sorted now,the yard been like this for over 15 years.

 

[Wilko]

Hi Cliffed, to clarify - the 4 core 35mm SWA is used to extend the 3 phase service from the TNCS PME DNO cutout. There are no connections to the cutout except via this SWA, so the armour is providing CPC for the SWA and earthing conductor function for the site?

4 core 35mm SWA has steel of 84mm and resistivity ratio given as 8.5 on p60 of GN8 meaning equivalent to 9.88mm of copper. Which means its undersized for current regs, which I think will be 10 or 16 from Table 54.8 (depends on incoming DNO neutral size).

I'm not familiar enough to know if it was sized ok for an earlier edition? In which case it could be a C3 improvement?

 

[cliffed]

Exactly right,the actual incoming neutral size is 240 mm,which I think gives a Earth bonding conductor of 50 mm.
Interesting to know the C3 code given

 

[westward10]

Hi Cliffed, to clarify - the 4 core 35mm SWA is used to extend the 3 phase service from the TNCS PME DNO cutout. There are no connections to the cutout except via this SWA, so the armour is providing CPC for the SWA and earthing conductor function for the site?

4 core 35mm SWA has steel of 84mm and resistivity ratio given as 8.5 on p60 of GN8 meaning equivalent to 9.88mm of copper. Which means its undersized for current regs, which I think will be 10 or 16 from Table 54.8 (depends on incoming DNO neutral size).

I'm not familiar enough to know if it was sized ok for an earlier edition? In which case it could be a C3 improvement?

I thought the ratio was 8, not at home to check.

 

[westward10]

Exactly right,the actual incoming neutral size is 240 mm,which I think gives a Earth bonding conductor of 50 mm.
Interesting to know the C3 code given

How do you know the supply neutral csa.

 

[cliffed]

How do you know the supply neutral csa.

It's a c/t arrangement & the supply tails to the Main panel are 240 mm & 120 mm main earth.
Main switch rated at 400 amps.

 

[cliffed]

How do you know the supply neutral csa.

I meant neutral size of the outgoing tails,soz