Hi all, I understand the need of an additional earthing rod in case the one provided by the dno is not available in eps mode. However, considering the level 1 solution of a single socket that becomes live in case of grid failure, would be earthing provided by the inverter (kh8), assuming the additional earth is provided at source or do I need to wire the ground from the rod separately for the emergency socket?
Also, does the socket need it's circuit breaker and rcd in that scenario?
Thank you in advance.
I've seen trailing leads or single sockets installed on the EPS, the caveat is that if the grid has failed then it is possible the grid incomer has been cut in which case you may not have an earth (unless you have a TT installation) hence the trailing lead/single socket could be un-earthed and hence rcd's etc.. will no longer work (a risk some people take)
If you fit an earth rod it should (according to regs) only be connected in the event of grid failure and so a c/o relay should be used to connect the earth rod to your house earth should the grid fail.
This is a good diagram that shows how EPS should be implemented download/file.php?id=753
There are solutions available that do all of the switching you require, clearly more expensive but very effective this post links you to a supplier that makes a c/o unit viewtopic.php?t=52&start=25 and this takes you straight to the suppliers product page https://www.eco-ess.co.uk/automatic-cha ... r-systems/
If you fit an earth rod it should (according to regs) only be connected in the event of grid failure and so a c/o relay should be used to connect the earth rod to your house earth should the grid fail.
This is a good diagram that shows how EPS should be implemented download/file.php?id=753
There are solutions available that do all of the switching you require, clearly more expensive but very effective this post links you to a supplier that makes a c/o unit viewtopic.php?t=52&start=25 and this takes you straight to the suppliers product page https://www.eco-ess.co.uk/automatic-cha ... r-systems/
Thanks Dave for the reply and for the diagram.
I wasn't aware that the earth rod could not be used/attached at the same time as the DNO provided earth, so that is great to know.
In my current setup without EPS, the earth used is from the grid (which is TN-C-S, as stated in the meter box).
What is unclear to me is what happens in the event that there is a grid failure but the earth is not compromised (e.g testing the EPS socket with a socket tester).
Does the KH inverter still provide earth via the EPS connector in that case?
If not, I guess that is safer to have earth rod connected directly to the socket and provide ground only effectively in case of emergency.
Thanks again, I appreciate all the info.
I wasn't aware that the earth rod could not be used/attached at the same time as the DNO provided earth, so that is great to know.
In my current setup without EPS, the earth used is from the grid (which is TN-C-S, as stated in the meter box).
What is unclear to me is what happens in the event that there is a grid failure but the earth is not compromised (e.g testing the EPS socket with a socket tester).
Does the KH inverter still provide earth via the EPS connector in that case?
If not, I guess that is safer to have earth rod connected directly to the socket and provide ground only effectively in case of emergency.
Thanks again, I appreciate all the info.
In a TN-C-S earthing system, there are only 2 feeds from the grid Live and Neutral and Neutral is split before the meter to provide an Earth (bonded N>E).
If the Earth is still present then you are still connected to grid Neutral and this is where it gets complicated, the regulations do not allow you to connect an islanded system to the grid as there is a danger to people working on the grid - that is why you should have a changeover switch to disconnect all of the incoming cores.
The later inverters such as KH and H1-G2 provide a Neutral>Earth bond relay when running in EPS, so when the grid fails you still have that bonded N>E in place (but no earth which is where the earth rod comes in).
Or you can use the earth rod as long as you disconnect the incoming grid before making the earth rod connection to the EPS earth.
But going back to your single socket EPS, there is nothing wrong with having a single socket for EPS as long as you only use class 2 (double insulated) devices on it.
If the Earth is still present then you are still connected to grid Neutral and this is where it gets complicated, the regulations do not allow you to connect an islanded system to the grid as there is a danger to people working on the grid - that is why you should have a changeover switch to disconnect all of the incoming cores.
The later inverters such as KH and H1-G2 provide a Neutral>Earth bond relay when running in EPS, so when the grid fails you still have that bonded N>E in place (but no earth which is where the earth rod comes in).
Or you can use the earth rod as long as you disconnect the incoming grid before making the earth rod connection to the EPS earth.
But going back to your single socket EPS, there is nothing wrong with having a single socket for EPS as long as you only use class 2 (double insulated) devices on it.
Thanks Dave, you have been super helpful.