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Earth leakage protection


isetech
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Simple you connect the inverter supply via the main DB which has earth leakage protection ... you fit a changeover switch on the output of the inverter and fit and earth leakage unit  and all the circuits will be protected

or 

You dont fit a changeover switch because you install a system with only 1 x 5 KVA or smaller and dont need to worry about a changeover switch ... so you connect the inverter via the main DB earth leakage through a 32 amp MCB  and fit an earth leakage unit at the output of the inverter.

The question ...

Is it that simple and what are the implications of connecting 2 earth leakage units in series ... do you have twice the the protection or nuisance tripping ... what happens if your main DB E/L unit is more sensitive than the one at the inverter output?

What If you only have the earth leakage connected in the main DB ... feeding the inverter is that adequate protection ... what happens if the 32 amp MCB trips and the inverter switches to backup and there is no earth leakage after the inverter?

Do you even need earth leakage protection from the main DB to the inverter ... and after the inverter for that matter ... if you are feeding "essential services" you dont need earth leakage protection (as per regs in SABS 10142-1)

Lastly ... so no earth leakage is required to feed the inverter ... however you have a changeover/bypass switch which will mean that if your earth lakage unit is connected to the output of the inverter ... by before the changeover switch ...when you switch to bypass all the circuit feeding the essential DB which require E/L protection will have no protection. 

Man and I thought this was going to be easy ... it works anyway you connect it ... its when things start going wrong that suddenly you realise ooops ...something is not right. 

Disclaimer: Just a newbie trying to work my way through the maize of information ... the more I read ... I realise how little I know ... please feel free to steer me in the right direction. 

 

Edited by isetech
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2 hours ago, isetech said:

Man and I thought this was going to be easy ... it works anyway you connect it ... its when things start going wrong that suddenly you realise ooops ...something is not right. 

That is so true and when you trough the SANS regulations into the mix you realize it is not that simple it takes a bit of thinking to get a legal COC.😂

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Get yourself an earth leakage tester and do the tests after all the wiring is completed.

It is interesting to see at what ma the rcd trips.

On 2021/02/17 at 6:41 PM, isetech said:

connecting 2 earth leakage units in series

It will work if the second one has its own earth (tip from Aus).

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