In one of our recent project. There are multiple generators and individually feeding to each MDBs. Consultant instructed to loop all the Generator Neutral between each generators. Our proposal to provide individual neutral earthing for each generators.
Is it advisable to loop Generator Neutral Earthing (These generators are not synchronizing)
I'm not sure I've pictured this correctly, but...
It sounds like you have several generators, but they're feeding completely separate systems - their outputs aren't being paralleled. In which case I'd expect there to be a N-PE link for each generator (if they were paralleled, there should be one link for all the generators connected together at any one time). If the overall systems (generators and everything they supply) are anywhere within reach of each other (e.g. within the same building) then I'd expect them to share the same earthing/bonding arrangements - which would in effect connect all the neutrals together. (If there were separate systems out of reach of each other you could have separate electrodes for each generator if you wanted, or still combine them altogether, whichever was least inconvenient).
Perhaps another option in theory is to have a combined N & PE conductor shared between the systems - but as that's prohibited on consumer's installations in the UK (by law), it's not a common way to do things here (they legal entity running the generators would have to be different to the consumer), but might be more usual elsewhere.
- Andy.
I'm not sure I've pictured this correctly, but...
It sounds like you have several generators, but they're feeding completely separate systems - their outputs aren't being paralleled. In which case I'd expect there to be a N-PE link for each generator (if they were paralleled, there should be one link for all the generators connected together at any one time). If the overall systems (generators and everything they supply) are anywhere within reach of each other (e.g. within the same building) then I'd expect them to share the same earthing/bonding arrangements - which would in effect connect all the neutrals together. (If there were separate systems out of reach of each other you could have separate electrodes for each generator if you wanted, or still combine them altogether, whichever was least inconvenient).
Perhaps another option in theory is to have a combined N & PE conductor shared between the systems - but as that's prohibited on consumer's installations in the UK (by law), it's not a common way to do things here (they legal entity running the generators would have to be different to the consumer), but might be more usual elsewhere.
- Andy.
Hi Mr.AJJewsbury
In which case I'd expect there to be a N-PE link for each generator - There is no N-PE link, Neutral and Body Earthing are separate network. Our projects in UAE and its a Data Center - Tier 3 Project.
there should be one link for all the generators connected together at any one time).- Each MDBs are connected separately and a separate network path to final Equipments/ Rack to maintain redundancy.
If the overall systems (generators and everything they supply) are anywhere within reach of each other (e.g. within the same building) -Yes 4 MDBs are fed by 4 individual Generators as well as Transformers.
(If there were separate systems out of reach of each other you could have separate electrodes for each generator ) - Separate Neutral earthing was considered for individual Generators and Body earthing for individual generators are lopped in between generators.
Our projects in UAE
So what standard(s) apply?
BS 7430: Code of Practice for Earthing
BS 7671: Requirements for Electrical Installations
NFPA 70: National Electrical Code.
BS 7430: Code of Practice for Earthing
BS 7671: Requirements for Electrical Installations
NFPA 70: National Electrical Code.
NFPA 70 is not compatible with BS 7671 and BS 7430 (and indeed IEC 60364 series). Some of the fundamental requirements conflict. It's not often possible to comply with both simultaneously.
Usually, there is a "precedence of standards" clause in either the Contract, the General Specification, or the Particular Specification, which says:
"UAE national standards take precedence over ..." etc. ? What does that say for this project?
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