No concept?

If you had two 30mA RCDs at each end of your sub-main, there is no guarantee which one would trip first, or even both would trip together, this means they won't discriminate with each other.

I usually prefer to have the RCD local (in the out building), as it is more convenient to re-set if it trips, instead of having to walk (possibly in darkness) some distance away to re-set.
 
Never said I would have a rcd at both ends, either a mains switch at mains with a local rcd in garage or rcd at mains with main switch in garage. So there would only ever be one rcd. Am no fool so please don't make out or judge my competence engineer54 I several years experience from bms, hvac inverter drives, trend plc programming from running a 56 flat domestic installation. I am no dummy but far from the best and always look to learn more
 
Or tripping over the old rake and it busting your nose!! My dad did that once and I literally wet my under crackers
 
Never said I would have a rcd at both ends, either a mains switch at mains with a local rcd in garage or rcd at mains with main switch in garage. So there would only ever be one rcd. Am no fool so please don't make out or judge my competence engineer54 I several years experience from bms, hvac inverter drives, trend plc programming from running a 56 flat domestic installation. I am no dummy but far from the best and always look to learn more

No one is questioning your competence mate, just that of the OP's
 
If you had two 30mA RCDs at each end of your sub-main, there is no guarantee which one would trip first, or even both would trip together, this means they won't discriminate with each other.

I usually prefer to have the RCD local (in the out building), as it is more convenient to re-set if it trips, instead of having to walk (possibly in darkness) some distance away to re-set.

Really makes you wonder doesn't it, and this is after 2 years of practicing on paying customers installations!! Another example of why there is no such thing as a Domestic Installer!!
 
Never said I would have a rcd at both ends, either a mains switch at mains with a local rcd in garage or rcd at mains with main switch in garage. So there would only ever be one rcd. Am no fool so please don't make out or judge my competence engineer54 I several years experience from bms, hvac inverter drives, trend plc programming from running a 56 flat domestic installation. I am no dummy but far from the best and always look to learn more

Then don't act like one then, because i had you mixed up with the OP!! lol!!
 
I was thinking like hang on am getting butchered here for making a observation, was nice testing the water though as I am new to this forum
 
I was just stating that a napit assessor had told me to when doing a garage or outbuilding installation u had to use a earth rod for the earth in the garage, I would of normally brought a 3core swa across and used a core for the earth. I just gave a brief description of how I would of done the job, then all hell broke loose
 
Well it proved both NIC and Napit talk ballocks lol, no doubt Elecsa do too!

I don't think I have ever asked them a question, most stuff I do is not part P anyway, I only keep it on for when my usual stuff goes quiet, so long as it pays for itself I keep it going, into my 4th year now, and with it being watered down recently it nearly didn't get renewed this year at all.
 
I was just stating that a napit assessor had told me to when doing a garage or outbuilding installation u had to use a earth rod for the earth in the garage, I would of normally brought a 3core swa across and used a core for the earth. I just gave a brief description of how I would of done the job, then all hell broke loose

If my assessor pulled me up on a job like this I would hand him the regs book and the pile of GNs and tell him to explain to me where I had done anything wrong, I would like to bet him next years fees he couldn't lol
 
I think i'm an excellent smeller, but even I ****ed that one.

Doesnt really work with the automatic edit..........p-i-s-s-e-d.

Am I in spoonerism territory now?
 
Last edited by a moderator:
I was just stating that a napit assessor had told me to when doing a garage or outbuilding installation u had to use a earth rod for the earth in the garage, I would of normally brought a 3core swa across and used a core for the earth. I just gave a brief description of how I would of done the job, then all hell broke loose
I had a NAPIT mcs assessor attempting to give me a non-conformity for not bonding the PV array frame to the MET on a system using an isolating transformer inverter.

Even back then, isolating transformer inverter should never have had the frame bonded unless it was an extraneous conductive part (not that the TL ones should have needed bonding either, but at least he would have been applying the guidance at the time correctly, even if the authors of the guide themselves had clearly stated that this sections was wrong and shouldn't be followed).... turned out he was a sodding gas fitter by trade.

In contrast my last napit assessor was alright.
 
Yeah my napit assessor is a spark and to be fair he knows his stuff and generally asks me some good questions which I always have to go and pull my regs book from its holster. But this earth rod thing just got me thinking why? Surely taking a earth from met is going to create a major increase to the pfc via a additional parallel path or am I totally wrong here
 
Just noticed that this thread on RCD's is 6 pages long? What does that tell you about posters knowledge of the regs?? It would have been quicker to pick up a regs book and read it yourselves.
 
Yeah my napit assessor is a spark and to be fair he knows his stuff and generally asks me some good questions which I always have to go and pull my regs book from its holster. But this earth rod thing just got me thinking why? Surely taking a earth from met is Not going to create a major increase to the pfc via a additional parallel path or am I totally wrong here

Taking your later comment into account I added the 'Not' for you,

Even if it did increase the PFC somewhat, it would still likely not increase the PFC above the 16kA conditional rating of the CU in domestic (Annexe ZA), unless you were right next to the sub-station lol


And to the other poster, there is not 6 pages about RCDs, if you care to have a read, a bit of confusion maybe lol, but not about RCDs.
 
It's just a bit crack, it's a forum after all ! I honestly cannot stand people for a disgusting attitude chill out
 

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Is RCD needed at both ends of armour feed to outbuilding
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Electrical Wiring, Theories and Regulations
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