OP
Piratepete
Thanks for your entertaining and informative (some) replies. Rather gobsmacked to see this continue for 5 pages!:angel_smile:
Pete
Pete
Discuss Bonding Gas Supply in an Outbuilding in the UK Electrical Forum area at ElectriciansForums.net
Why should the sub-main earth be a minimum of 10mm? Doesn't table 54.7 apply for a PME supply? Also Table 4.4 (clearer) in the On Site Guide. 6mm supply 6mm earth. Or have I missed something?NO, it doesn't negate main bonding to the outbuildings CU (EMT) especially if the supply is PME, in which case the sub-main earth should be a minimum of 10mm....
Why should the sub-main earth be a minimum of 10mm? Doesn't table 54.7 apply for a PME supply? Also Table 4.4 (clearer) in the On Site Guide. 6mm supply 6mm earth. Or have I missed something?
Cheers
Pete
Thanks for your entertaining and informative (some) replies. Rather gobsmacked to see this continue for 5 pages!:angel_smile:
Pete
Why should the sub-main earth be a minimum of 10mm? Doesn't table 54.7 apply for a PME supply? Also Table 4.4 (clearer) in the On Site Guide. 6mm supply 6mm earth. Or have I missed something?
Cheers
Pete
Minimum size of a main bond on a PME supply is 10mm. Main bonds must be sized according to the incoming service not for the size of any submains.
Have a look at Regulation 543.1.1 and 544.1.1
Read my text. I'm querying the sub-main earth size, not main bonding.
The point being made is that if bonding is required at the remote end of the sub-main, then that sub-main's CPC will be required to be sized to act as both a CPC and a main bonding conductor, which means the sub-mains CPC will need to be 10mm minimum to satisfy the PME regs.
But the whole purpose of this thread is about bonding the gas supply in an out building.
If you connect your 10mm bond to the EMT in the outbuilding then the CPC in the cable feeding the sub board in the outbuilding will have to be adequate to comply with the minimum CSA of the bond to the gas. For example it's no good having a 6mm 3core SWA feeding the sub board in the outbuilding when you are required to bond the gas in the out building in 10mm (if it's TNC-S), The CPC in the sub main cable would have to Adequately sized for the bond as well.
Ok. I can see where you're coming from, but can you please explain the application of the first 2 columns in table 4.4 On Site Guide?
Ok. I can see where you're coming from, but can you please explain the application of the first 2 columns in table 4.4 On Site Guide?
Ok. I can see where you're coming from, but can you please explain the application of the first 2 columns in table 4.4 On Site Guide?
What is there to explain ?
As you go down those first two columns in 4.4 (i) it gives the minimum sizes according to function of said conductor, obviously if it is only an EC then the minimum size is given, likewise for a MPB, where it is used as both functions again the minimum size is given, so a combined EC and MPB then the minimum size for the MPB is used (or whichever is the larger minimum size to satisfy that particular requirement/s), the last row in that table refers specifically to PME/TNC-S, as that table covers both TNS an TNC-S systems, table 4.4 (ii) being for TT
The lack of main bonding to a service?
Have a look for guidance (ie the esc or whatever its called lately)as to the code,that is until your experience allows you to answer these questions when you do start carrying out Eicrs in the future
http://www.electricalsafetyfirst.org.uk/mediafile/100126678/best-Practice-Guide-4.pdf
Have a read through this but ultimately it's you that decides what code to give to any given situation as you are the inspector and signing the report, this is only a guide.
Reply to Bonding Gas Supply in an Outbuilding in the UK Electrical Forum area at ElectriciansForums.net
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