Testing RCD on shower circuit

[voltage]

This is a picture i've taken of my megger and test leads connected to do the RCD test on my mk dual RCD board

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Obviously i have not put the busbar in yet but u get the drift.

Main switch on MCBs off RCD ON then test load side of RCD line to earth for that particular RCD or like not so clever pointed out if the RCD side you are testing has a circuit using socket outlets then just use the plug on the megger and test at socket outlet.
first test 1/2 then 1 then 180 wave then 5 then 180 wave record two highest results. The 1/2 test should not trip this is a test to gauge how sensitive the RCD might be ?
Then finally test the manual button on the RCD to see if it works.

 

[IQ Electrical]

Looks fine, you do your tests right there on that RCD and the results will apply to the 4 circuits protected by that RCD.

 

[voltage]

yeah thanks then ill repeat the same test for the second RCD and that will take into account the 3 circuits on that RCD.
Thanks for fast reply volt.

 

[telectrix]

personally, i just plug in to the nearest socket outlet, with loads removed. problem with using probes is breaking a connection when resetting the RCD. it's rare to find a RCD without at least 1 socket circuit on it. ( RCBOs excepted )

 

[richy3333]

And finally... complete your ramp test

 

[Amp David]

It's a 2-lead test on the 1553.

.

Thank god for that. Just read the post saying use 3 leads a started thinking i've been doing it wrong using the Megger.

 

[jamminuk]

Hi,

Sorry to jump in on this one but, something i come accross the other day, old style re-wirable fuse board with a completely separate rcd for the shower, the pull cord switch went in the bathroom so i just replaced it like for like, the rcd was operating mechanically but how would i test it at the shower/pull switch? (I've disconnected it for the time being). Can i just connect the leads at the pull switch? just seems a bit unsafe doing it this way as obviously it's a live test?

Thanks

Ben

 

[malcolmsanford]

You can do it there or at the the RCD itself. Better at the RCD itself as you won't have to test on a switch which is over head.

 

[telectrix]

test at the CU. it's easier. switch off all MCBs on the RCD you are testing. clip to earth bar, probe to L on load side of RCD. ( mft set to RCDauto ). switch on RCD, press test button on MFT. reset RCD each time it trips. read off and record trip times. enter the higher of each on schedule of test results. press test button on RCD to confirm operation. ramp test if required. done.

 

[jamminuk]

Still not sure as it's on re-wireable fuse board, shower circuit doesn't even go through the main fuse board, it's located separately mounted below. I thought rcd was live test?

 

[robskiing]

test at the CU. it's easier. switch off all MCBs on the RCD you are testing. clip to earth bar, probe to L on load side of RCD. ( mft set to RCDauto ). switch on RCD, press test button on MFT. reset RCD each time it trips. read off and record trip times. enter the higher of each on schedule of test results. press test button on RCD to confirm operation. ramp test if required. done.

Yes it is a live test just follow the above instructions easier than any manual

 

[malcolmsanford]

It is a live test, you test it live with your probes, as Tel highlighted one probe croc clipped to the earth bar and with the other probe on the load side of the RCD. Is the RCD fed from a re-wirable fuse?

 

[jamminuk]

From what i can remember it looks like it was fed directly from the meter tails, 1 set goes to the main fuse board another set go into a separate RCD then onto the shower pull switch. Also whe i was taking the switch down i had a small shock off of the earth wire, is this normal? i performed an IR test between live and earth and it came back ok, not sure why there would be any current/voltage in the earth wire. I noticed something on here about earth leakage but this is a completely separate circuit for the shower, nothing to get leakage from, confused.com

Regards

Ben

 

[robskiing]

If you can get back to that job take a picture of the rcd unit showing the meter and cut out is there an earth wire from the incoming supply up to you rcd unit

 

[malcolmsanford]

If your getting a tingle of the earth, it could mean that the CPC is not connected somewhere or the neutral is loose somewhere.

Also if the RCD is fed direct of the tails then you don't seem to have any overload protection.

 

[jamminuk]

Asked the guy to take a picture and email it to me

 

[telectrix]

as you describe it, there should be a MCB alongside the RCD ( 40A? ). if not, then as malcolm says, no overload protection for the shower cable = FIRE.

 

[IQ Electrical]

as you describe it, there should be a MCB alongside the RCD ( 40A? ). if not, then as malcolm says, no overload protection for the shower cable = FIRE.

Is a shower not a fixed load?

 

[malcolmsanford]

Is a shower not a fixed load?

It is mate, but I still don't like personally going down that road of not having overload protection. I know 433.3.1 (ii) but I still like to have that safeguard, old habits I assume.

 

[IQ Electrical]

It is mate, but I still don't like personally going down that road of not having overload protection. I know 433.3.1 (ii) but I still like to have that safeguard, old habits I assume.

I agree, I'm stirring the pot