Not protected by RCD
What do you mean by main side?
Discuss Testing garage CU for assesment!!! in the UK Electrical Forum area at ElectriciansForums.net
What do you mean by main side?
Didnt opt to use PME from house, instead earth staked the outside building. Obviously a big no no from the sparks on here. Thanks
Didnt opt to use PME from house, instead earth staked the outside building. Obviously a big no no from the sparks on here. Thanks
It’s not a big no no, it is sometimes necessary to do this, however in your installation it sounds like there were better options.
Unless your earth electrode has a stable Ra somewhere below 1ohm then you’d be better off having used the TNCS earth in my opinion.
How have you isolated the earth of the SWA at the load end of the cable? Which earthing system have you connected the armour of the SWA to?
Merely putting in an earth electrode at the shed end won’t prevent the RCD in the house from tripping. The neutral is still referenced to true earth at the substation so the RCD will see the imbalance from any earth fault or leakage. To achieve what you want you would need to install an isolating transformer and set up a TNS supply to the shed by referencing one leg of the output to earth.
This hasnt even touched on the subject of discrimination and why feeding a submain from an mcb is rarely the best practice.
I realise you only asked about testing, but all of the points raised should also come up during your NIC assessment
What he said^^^^^^^^^^^^^^^What do you mean by main side?
All I asked was advice about testing. Thanks
AbsolutelyMy only other comment is to use 3 core in the future ... and a switch fuse.
Can I ask why the OP is being recommended to not use a not RCD protected way in the house CU, with RCD CU in log cabin, presuming he uses the PME?
Sorry Murdoch, you've mentioned using a switch fuse (#36) and Davesparks said 'why feeding a submain from an mcb is rarely the best practice' (#33). I understand the use of a switch fuse feeding a distribution circuit for a domestic property CU, but for a small CU for a log cabin or garage etc?You lost me with that ... but I simply questioned why he would purposely have 2 x RCD's in series...
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