E
EastAnglian
I've just completed an EICR on a 5 year old re-wire in a village hall (not mine!).
Before committing to paper I'd like to check 2 of my (unrelated) observations here:
(1) Heaters
3 x 3kW heaters installed on a single 32A MCB, switched via a contactor located on the board.
Cable from MCB to contactor = 4mm
Individual cables to heaters from the output of the contactor = 2.5mm T&E (all run in trunking, several metres length)
I contend that the 2.5mm cable is undersized for the 32A protective device and that 433.3.1 can only be applied if the adiabatic equation in 434.5.2 is satisfied.
Would you agree?
(2) Metal DB on TT system
Its a TT system. A metal DB has been used with an RCD main switch on the DB . Short tails to DB. I feel on safe ground here that this is incorrect but is 531.4.1 the correct reference to quote to justify that the RCD must be located at the origin as the external conductive part which is the case of the DB is not protected?
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I'm keen to get this right as they may want to refer this back to the original installer if there are deficiencies in the design & installation.
Thanks
Malcolm
Before committing to paper I'd like to check 2 of my (unrelated) observations here:
(1) Heaters
3 x 3kW heaters installed on a single 32A MCB, switched via a contactor located on the board.
Cable from MCB to contactor = 4mm
Individual cables to heaters from the output of the contactor = 2.5mm T&E (all run in trunking, several metres length)
I contend that the 2.5mm cable is undersized for the 32A protective device and that 433.3.1 can only be applied if the adiabatic equation in 434.5.2 is satisfied.
Would you agree?
(2) Metal DB on TT system
Its a TT system. A metal DB has been used with an RCD main switch on the DB . Short tails to DB. I feel on safe ground here that this is incorrect but is 531.4.1 the correct reference to quote to justify that the RCD must be located at the origin as the external conductive part which is the case of the DB is not protected?
------------------
I'm keen to get this right as they may want to refer this back to the original installer if there are deficiencies in the design & installation.
Thanks
Malcolm