Live testing - could this be a Part P assessment failure?

[Tuttle]

Another Part P assessment related question ...

What is the correct way of carrying out RCD tests on RCBO protected circuits that have no socket outlets, e.g. lighting, alarms, immersion heaters, etc?

I would be tempted to switch on the main switch and the RCBO for the circuit to be tested with the CU cover removed, just for the duration of the test, and probe the neutral and live terminals on the top of the RCBO with my multifunction tester's leads (with GS38 covers fitted) but I am a little concerned that this would be classed as working live.

Is it acceptable to energise the CU with the cover off in this case or would I risk failing my assessment?

Anyone done this on an assessment? Was it ok or frowned upon?

Seems like the safest way to do it to me but I am not sure if switching on with the cover removed is a big no no in all situations.

 

[johnboy6083]

live working is a part of testing that cannot be avoided if it is to be done properly

 

[Tuttle]

Another Part P assessment related question ...

What is the correct way of carrying out RCD tests on RCBO protected circuits that have no socket outlets, e.g. lighting, alarms, immersion heaters, etc?

I would be tempted to switch on the main switch and the RCBO for the circuit to be tested with the CU cover removed, just for the duration of the test, and probe the neutral and live terminals on the top of the RCBO with my multifunction tester's leads (with GS38 covers fitted) but I am a little concerned that this would be classed as working live.

Is it acceptable to energise the CU with the cover off in this case or would I risk failing my assessment?

Anyone done this on an assessment? Was it ok or frowned upon?

Seems like the safest way to do it to me but I am not sure if switching on with the cover removed is a big no no in all situations.

BTW. I meant neutral and line terminals - thought I'd get that in before anyone points out that the neutral is a live conductor

 

[needasparks]

There is not normally any reason to remove the cover without the main switch off that i can think of (although we all do it ) but don't do it on an assesment.
Why are you testing the circuit(rcd) at the origin and not at the end of the circuit under test ? What is this going to achieve ?

 

[Tuttle]

There is not normally any reason to remove the cover without the main switch off that i can think of (although we all do it ) but don't do it on an assesment.
Why are you testing the circuit(rcd) at the origin and not at the end of the circuit under test ? What is this going to achieve ?

The reason for testing at the origin is that it is easier (safer I think) than trying to probe live connections in a ceiling rose or dismantling a live fused connection unit or alarm panel. Also, I'd have to walk away from the dismantled equipment to reset the RCBO.

 

[trev]

Another Part P assessment related question ...

1)What is the correct way of carrying out RCD tests on RCBO protected circuits that have no socket outlets, e.g. lighting, alarms, immersion heaters, etc?

2)I would be tempted to switch on the main switch and the RCBO for the circuit to be tested with the CU cover removed, just for the duration of the test, and probe the neutral and live terminals on the top of the RCBO with my multifunction tester's leads (with GS38 covers fitted) but I am a little concerned that this would be classed as working live.

3)Is it acceptable to energise the CU with the cover off in this case or would I risk failing my assessment?

Anyone done this on an assessment? Was it ok or frowned upon?

Seems like the safest way to do it to me but I am not sure if switching on with the cover removed is a big no no in all situations.

1) Instead of the lead with the plug top use the one with the probes and fit your crocs on th ends, attach relevant croc to terminal and hit button for test as normal
2) What would you be hoping to achieve with this method? The way to do it is to test at the point furthest remote from the origin. You would be testing live at this stage. To complete the testing function properly live tests are inevitable
3) Don't know for sure whether it would fail you your part p assessment but I do remember that taking the cover off a live CU during 2391 practical was an instant fail

 

[trev]

The reason for testing at the origin is that it is easier (safer I think) than trying to probe live connections in a ceiling rose or dismantling a live fused connection unit or alarm panel. Also, I'd have to walk away from the dismantled equipment to reset the RCBO.

If you did that and something went wrong and it ended up in front of a guy in a wig and a robe what would your reply be to the question "Why did you not conduct the tests in accordance with normal custom and practice and as laid down in guidance note 3?"

 

[needasparks]

But you would not have resistance values added to the result of the rcd triping time would you ?
We have also got to find a way of a safe testing method for the situation which is why we are assesed on our proceedures. sometimes we have to use two people for live testing for that reason if concidered needed. It goes with the job i'm affaid.

 

[trev]

Even if you didn't have someone with you you could establish exclusion zones around the open live points with barriers around them + big signs "DANGER 230/400 VOLTS NO ENTRY DANGER OF DEATH" etc.
Put em up take photos on your phone as proof they were there, test as per usual, jobs a goodun

 

[Tuttle]

The on site guide says that RCD tests are made on the load side of the RCD "as near as practicable to its point of installation" which seems to me to say that the tests don't need to be carried out at the furthest point, in fact I think that it says that test should be carried out near to the origin if that is where the RCD is installed, or have I misunderstood?

I've got GN3 here so I'll have a look through that as well (can anyone point me at the relevant bits?).

 

[Tuttle]

I can't find anywhere in GN3 that specifies where RCD testing should be performed, e.g. the origin / point of installation or the furthest point. Actually, I wouldn't have thought that it would make much difference anyway because the tester draws a constant current so circuit resistances should not have an effect, and the aim of the test is to test the RCD not the wiring. I thought the CU would be a good place to do live testing (if there is no better alternative) as there is good access, it is fixed to the wall not floating around, and on a modern unit with the bus bar cover fitted there is not really that much to accidentally touch - much safer than an old CU switched off with the lid off! - but maybe I need to rethink

 

[netblindpaul]

You should NOT undertake RCD tests at circuit extremities as the testers that are in use for this are in adequate to deal with this scenario.
RCD tests must be undertaken at the output of the RCD to be accurate unless you have an RCD tester which is genuinely costing about £10k+!

 

[jaresquire]

My NIC inspector has no problem with testing rcd/rcbo at the cu.

 

[trev]

Fair enough chaps, I appear to be wrong. Although I've always carried out RCD test at the furthest point and did so on my 2391 practical too. I stand corrected

 

[Tuttle]

You should NOT undertake RCD tests at circuit extremities as the testers that are in use for this are in adequate to deal with this scenario.
RCD tests must be undertaken at the output of the RCD to be accurate unless you have an RCD tester which is genuinely costing about £10k+!

I had wondered why OSG says to test close to the point of installation, and that could explain it, thanks