Maximum tolerable fault current

[TALK]

Just completing the testing of a transportable catering unit.(chip van). Within the NICEIC REPORT I must complete,

a.MAXIMUM TOLERABLE FAULT CURRENT(is the same as PSCC)?

b.MAXIMUM TOLERABLE UPSTREAM ELI.(is this the same as Zs)?

If so how do I achieve these values when the Power Transformer/Generator is different at every site,or would this mean a report must be completed at every site,every time the catering unit moves.

This unit moves 3 times a week.

Thanks for your help.

 

[Deleted member 26818]

I would suggest that maximum tolerable fault current refers to the maximum before damage occurs.
So if the connection is made direct into the unit's CU, which should be rated at 16kA, the maximum tolerable fault current would be 16kA.
Whereas if the connection is made via a plug and socket rated at 6kA, the maximum tolerable fault current would be 6kA.
This would be PFC.
The maximum tolerable upstream ELI would be the maximum Ze that the unit can be connected to and still allow ADS to be achieved.
For instance if yout unit just had lighting on a 6A type B MCB, the maximum Zs would be 7.67Ω. If the resistance of the unit's wiring between the connection point and the furthest lighting point was 1Ω, the the maximum tolerable upstream ELI would be 6.67Ω.
If however the unit had both lighting and socket-outlets, and the socket-outlets were protected by a 16A type B MCB, the maximum Zs would be 2.87Ω. If the unit's wiring was again 1Ω, then the maximum tolerable upstream ELI would be only 1.87Ω.

 

[telectrix]

well put spin, clear and concise. better than i could have explained it.