EICR codes for SY cable and biomass install

[vxwestie]

I've got a new installation within a biomass boiler building connected to an installation I've just carried out.
The boiler room install has been carried out by a non registered contractor and as it's been connected to my install, I've been asked to carry out an EICR by the client.
The installer has said they will issue a completion cert, but to date nothing has appeared and the client inst happy.
the boiler room in 100m from my installation and connected to a 45amp isolator I've wired in 10mm t&e in the main house.
The boiler company has installed a 35mm swa connected to this isolator and have exported the PME.
ZS At the boiler house is 0.99 ohms, border line for the 45amp supply mcb and they have relied upon my 30ma RCD in the house to protect the boiler, sockets, lights etc.
the boiler room contains a mass of large copper and steel pipe work and there is no earthing or bonding to this whatsoever.
ive got a few things to say about this, however also all the wiring in the boiler house has been done in SY flex from the dis board. Normal Trs glands have been used and none of the screening of the SY cable has been earthed.
All the cabling within the boiler room is on steel tray, there is no bonding or earthing to the tray either.
Your thoughts on this, codes and what code for the SY connections please gentlemen (and ladies)
discuss....
its on of those I need to be sure of what I'm saying and claiming before the **** hits the fan...

 

[telectrix]

C2's in my book.

 

[vxwestie]

Agreed. But I'm swaying towards c1 for the bonding of the services and conductive parts. Need to have a good read of the jolly green book when I get home ...

 

[vxwestie]

Just can't believe they'd rely on exporting the pme (especially when the isolator supply had only a small cpc in the t&e.
Also relying on the RCD socket a 100m away in the main house for the socket outlet is questionable..

 

[Richard Burns]

Zs does not comply with disconnection times (as 45A BS60898 Type B need 0.86Ω), however the prescence of a 30mA RCD extends the Zs to 1667Ω so no code, but not good practice.
Exposed conductive parts (sheath of SY) not earthed so could become live in the case of a fault so C2.
Boiler pipe work presumably would not introduce an earth potential in the boiler house but pipework also is expected to be continuous back to the house where it is bonded, no code.
If the pipework passes underground between the boiler house and the CU then it may introduce an earth potential and should be bonded back to the MET, if this is the case, then C2.
Failing to put two 30mA RCDs in series, good practice, no code.
From what you describe there is no case where live parts are available to touch or suchlike so there are no immediate dangers so no C1 codes.

 

[vxwestie]

Mmmmm gonna have to read up on the pipe work bit. I'm just not happy with no earthing, I certainly wouldn't have done it like that. The main water supply comes into the boiler house, then the supply and heating pipes run underground in thermoplastic, I believe, pipe. Personally I would have treated it as a separate installation with separate earthing requirements. Like you say, it does seem mostly like c2s, just a a bit of a bodge really...

 

[Richard Burns]

OK main water supply comes into boiler house.
Is it extraneous? Is it a metal incomer?
If so then the easiest thing is to have an earth marshaling terminal in the boiler house and take the bonding back from there to the MET.

If the pipework goes underground in thermoplastic then this will not introduce an earth potential and would not then need bonding once it arrives at the other end.

To separate the installation would require the boiler house to have a TT system in place which, whilst a good system, is more dangerous than using a TNCS system that is already present.
However the consideration of bonding is a tricky one and generally a nuisance!
As it is in this case.
It does sound like it has been installed by someone who can connect wiring but has little in depth knowledge of how installations should be designed.

 

[vxwestie]

Totally agree. It's one of the worse things when it's new and not done the way you'd do it. I think I'd would have gone TT and treated it as two installations.
Its not helped by the fact that the confirmed ze for the installation from the DNO is 0.36ohms.
I personally feel that with numerous amounts of pumps, control gear and boiler in the biomass building there is risk of a earth potential into the system under fault conditions and just don't like the amount of metallic parts unearthed..

 

[Plonker 3]

I personally feel that with numerous amounts of pumps, control gear and boiler in the biomass building there is risk of a earth potential into the system under fault conditions and just don't like the amount of metallic parts unearthed..

Cockburn is that you?

 

[Engineer54]

Zs does not comply with disconnection times (as 45A BS60898 Type B need 0.86Ω), however the prescence of a 30mA RCD extends the Zs to 1667Ω so no code, but not good practice.
Exposed conductive parts (sheath of SY) not earthed so could become live in the case of a fault so C2.
Boiler pipe work presumably would not introduce an earth potential in the boiler house but pipework also is expected to be continuous back to the house where it is bonded, no code.
If the pipework passes underground between the boiler house and the CU then it may introduce an earth potential and should be bonded back to the MET, if this is the case, then C2.
Failing to put two 30mA RCDs in series, good practice, no code.
From what you describe there is no case where live parts are available to touch or suchlike so there are no immediate dangers so no C1 codes.

A/ however the prescence of a 30mA RCD extends the Zs to 1667Ω so no code, but not good practice.
This is a ''New'' installation, there is no excuse to use an RCD devices 1667 Ohms to circumvent an installed non complying Zs....

B/ Boiler pipe work presumably would not introduce an earth potential in the boiler house but pipework also is expected to be continuous back to the house where it is bonded, no code.
Separate building, so bonding ''IS'' required at the boiler house, you Don't rely on a remote service bond located within a different building...

C/ If the pipework passes underground between the boiler house and the CU then it may introduce an earth potential and should be bonded back to the MET,
There is no maybe about it, any metal pipework buried for 100m underground ''WILL'' be carrying an extraneous potential. As above, but connected to the boiler house EMT.


A 10mm T&E supply for a building that is going to be located 100m away isn't very forward thinking either. Even the 35mm SWA cable from the 45A isolator isn't gong to any good unless it's a 3 core cable, you can't use the steel wire armour as a combined CPC/Bonding cable, especially on a PME/TNC-S installation.

 

[Megavolt]

100% of all biomas installs we have done has plastic district heating pipe work linking buildings. Some pellet on site once told me he wouldn't commission boiler unless pipe work was bonded.

 

[Darkwood]

Vx you say they have exported the PME ..if so Id be condemning the install and disconnecting it as its illegal to do so without DNO permission.... what I think you mean is they have extended the the equipotential zone, a very different thing, if your writing up a report on this make sure you get your terminology correct as it will be most likely contended by the boiler company.