H
harry98
Hi could someone please explain why you cant export a PME over 20 metres?
And what are the dangers of doing so?
Cheers
And what are the dangers of doing so?
Cheers
Discuss Exporting PME in the Electrical Wiring, Theories and Regulations area at ElectriciansForums.net
You can export a PME supply to an outbuilding providing that the outbuilding in question has no structural steel metalwork. If it has, a TT supply feeding an RCD protected CU is required, all structural steel is to be bonded and an earth rod installed. The danger with PME is if the neutral conductor fails, extraneous metalwork is used as the return path for the supply.
Hi Shakey. If the supply to an outbuilding is going to be TN-S, then I'd put the RCD at the supply end because you'd have a continuous earth from the house to the outbuilding via the armouring and maybe a spare cable conductor. If the supply is PME and you're not connecting the armouring at the outbuilding, the RCD wouldn't work as they'd be no return earth path for fault current. Provided that you can guarantee a disconnection time of 0.4s or less, the cable can be protected by an MCB.
You can export a PME supply to an outbuilding providing that the outbuilding in question has no structural steel metalwork. If it has, a TT supply feeding an RCD protected CU is required, all structural steel is to be bonded and an earth rod installed. The danger with PME is if the neutral conductor fails, extraneous metalwork is used as the return path for the supply.
Reply to Exporting PME in the Electrical Wiring, Theories and Regulations area at ElectriciansForums.net
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