RCD testing

[voltage]

Hey guys

As you guys know i've got my NICEIC assessment soonish and im performing some of the test sequences at my house.
Reguarding RCD testing my multifunction tester is a megger 1553 so i just want to run over a few things with you guys.

Im going to perform the RCD test via the downstairs socket outlets which is covered by the RCD.

So at the consumer unit do i turn off all other MCBs and just leave the 32amp MCB on for the sockets downstairs and then unplug all equipment plugged into downstairs sockets ? or can i leave everything plugged in while i perform the tests ?


Any help or info would be appreciated many thanks guys

 

[malcolmsanford]

No you should remove all loads from the socket outlets, and switch off any double pole switches such as FCU's. If you don't there is a good chance you will get a false reading.

Yes I would isolate all the other MCB's that the RCD covers, which is often why I prefer to do the RCD test at the CU, with all the MCB's shut of. It saves on unplugging everthing in sockets, and keep walking back and forward from socket to RCD. Which is often when I do a re-wire or new wire I fit a couple of single 13amp sockets next to the board for each RCD, for ease of testing in the future.

 

[voltage]

thanks for reply malc. So at the consumer unit then i can turn off all MCBs and just leave the RCD on and test it that way without having to unplug everything from sockets ?

 

[malcolmsanford]

Yes you would test with the leads with the RCD still on and all MCBs off.

 

[Chr!s]

Also dependent upon installation conditions, you may need to disconnect the common neutral. Certain types of faults can effect the testing of the RCD'S.

 

[steamboatwilly]

No you should remove all loads from the socket outlets, and switch off any double pole switches such as FCU's. If you don't there is a good chance you will get a false reading....

Yes, this caught me out on my NIC inspection a couple of years ago....a simple radial but there was a freezer plugged into the end socket and I couldn't get proper readings with it plugged in. Inspector spotted it.

 

[Dunc]

If you don't there is a good chance you will get a false reading.

Not to mention the fact that you may also end up damaging some equipment still on the circuit by turning it on and off 4 times in quick succession. It can happen believe me hence the reason why i always test the RCD at source with all MCBs isolated.

 

[Mfctitch]

Evening Everyone
I'm fairly new to this forum so forgive me if I'm doing this the wrong way round.
But Like voltage I too am retaking my NICEIC, kicked out last time because of not putting paperwork in :-(. Hope that I have learned my lesson.
Anyway I digress This is to malcolmsanford. I like you idea of just testing the RCD But could you explain in a bit more detail how you would go about this. Sorry if it seems such a stupid question but I have only ever tested by plugging my robin into the socket.
cheers

 

[telectrix]

Evening Everyone
I'm fairly new to this forum so forgive me if I'm doing this the wrong way round.
But Like voltage I too am retaking my NICEIC, kicked out last time because of not putting paperwork in :-(. Hope that I have learned my lesson.
Anyway I digress This is to malcolmsanford. I like you idea of just testing the RCD But could you explain in a bit more detail how you would go about this. Sorry if it seems such a stupid question but I have only ever tested by plugging my robin into the socket.
cheers

you would use 3 leads. connect black and green to Earth conductor, red to L on RCD. ( with RCD ON, and all MCBs OFF ) then test either manually or auto. at least that is with the 1552. i assume the 1553 is the same.

not sure of the procedure for the robin though, never useds one.

 

[voltage]

you would use 3 leads. connect black and green to Earth conductor, red to L on RCD. ( with RCD ON, and all MCBs OFF ) then test either manually or auto. at least that is with the 1552. i assume the 1553 is the same.

not sure of the procedure for the robin though, never useds one.

So on the 3 lead test method you would turn main switch off on consumer unit then remove consumer unit cover.

Safely isolate and prove everything is dead b4 commencing.

Then connect black and green leads using croc connections onto the earth terminal block ? then using the red probe put this on the line terminal of the load side of the RCD with the main switch on RCD on and all MCBs off is this correct ?

Using this method this means you dont have to unplug all equipment as you have all MCBs off and are testing the RCD direct ? correct ?

Any help would be greatly appreciated many thanks.

 

[malcolmsanford]

Yes that is exactly how you do it .................all I can't confirm is the lead connections as I don't use Megger, but if Tel says that is the connections then that is it.

 

[voltage]

ive got a picture here on my dummy board to see if this is correct

surely i only need the green lead on earth terminal not the black aswell ? can anyone confirm this please many thanks.

thanks for your response malc much appreciated thank you

 

[telectrix]

So on the 3 lead test method you would turn main switch off on consumer unit then remove consumer unit cover.

Safely isolate and prove everything is dead b4 commencing.

Then connect black and green leads using croc connections onto the earth terminal block ? then using the red probe put this on the line terminal of the load side of the RCD with the main switch on RCD on and all MCBs off is this correct ?

Using this method this means you dont have to unplug all equipment as you have all MCBs off and are testing the RCD direct ? correct ?

Any help would be greatly appreciated many thanks.

sounds right to me. if you've got the quick start guide to the megger, it's described in there.

 

[telectrix]

just re-read the megger giude. you are correct in saying that you can use just the red and green. however for auto test, the guide recommends using 3 leads, black and green commoned together on earth. don't know why though as the black is not connected into the tester. will have to contact megger. so, red and green it is.

 

[voltage]

thanks so just red and green lead. I will most likely do the test manually rather than auto so i can get the hang of all aspects.
Yeah my megger is the 1553 and in the quick start guide it gives you 3 options for RCD testing and then underneath that it tells you how to perform the RCD auto test sequence many thanks tele spot on advice as usual many thanks mate.

option 1 is green and red lead
option 2 is green and the probe
option 3 is mains plug lead which i no how to do.

thanks for the replies gys much appreciated