IR testing an individual circuit within con/unit

[driverman]

Hi,
When carrying out an IR test on a circuit within a consumer unit, can it be carried out safely with all the other circuits on?
Can the circuit under test be isolated by switching off protective device (MCB)? Under 2395 exam would MCB have to be locked off also?
Or would it be better to isolate the whole installation and lock off at main switch. Thanks

 

[Lukethoma1985]

Under an exam, i would isolate the whole board and lock off the main switch. Dont think they would like you working around live parts. One slip onto the bus bar.

 

[Geordie Spark]

Under an exam, i would isolate the whole board and lock off the main switch. Dont think they would like you working around live parts. One slip onto the bus bar.

Oh yes .. we must always practice Safe Isolation and do so BEFORE we take the cover off the CU mustn't we??

 

[driverman]

OK point taken..Lets say typical domestic property.....1 x Split board Con/ unit. The only way to isolate all the circuits is by switching off the main 100amp DP switch within the con/unit. Can the switch be safely locked "off" before the lid is removed?

 

[Geordie Spark]

OK point taken..Lets say typical domestic property.....1 x Split board Con/ unit. The only way to isolate all the circuits is by switching off the main 100amp DP switch within the con/unit. Can the switch be safely locked "off" before the lid is removed?

The switch is (usually) twice the width of (say) an MCB. The lock-off device I have is just slightly narrower than an MCB.

Therefore, I can fit it to the toggle of a Main Switch and still be able to remove the cover.

If this link works, you'll see what I use Wylex MCB Padlocking Kit | Screwfix.com

 

[davethsparky]

welcome to catch 22.
You must carry out safe isolation before you take the lid off.
Safe isolation requires you to prove that the thing is dead by testing and then proving your tester.
You have to take the lid off to get to the terminals to test.
You must carry out safe isolation before you take the lid off.
Safe isolation requires you to prove that the thing is dead by testing and then proving your tester.
You have to take the lid off to get to the terminals to test.
You must carry out safe isolation before you take the lid off.
Safe isolation requires you to prove that the thing is dead by testing and then proving your tester.
You have to take the lid off to get to the terminals to test.
You must carry out safe isolation before you take the lid off.

 

[driverman]

welcome to catch 22.
You must carry out safe isolation before you take the lid off.
Safe isolation requires you to prove that the thing is dead by testing and then proving your tester.
You have to take the lid off to get to the terminals to test.
You must carry out safe isolation before you take the lid off.
Safe isolation requires you to prove that the thing is dead by testing and then proving your tester.
You have to take the lid off to get to the terminals to test.
You must carry out safe isolation before you take the lid off.
Safe isolation requires you to prove that the thing is dead by testing and then proving your tester.
You have to take the lid off to get to the terminals to test.
You must carry out safe isolation before you take the lid off.

And your point is? lol

 

[Geordie Spark]

welcome to catch 22.
You must carry out safe isolation before you take the lid off.
Safe isolation requires you to prove that the thing is dead by testing and then proving your tester.
You have to take the lid off to get to the terminals to test.
You must carry out safe isolation before you take the lid off.
Safe isolation requires you to prove that the thing is dead by testing and then proving your tester.
You have to take the lid off to get to the terminals to test.
You must carry out safe isolation before you take the lid off.
Safe isolation requires you to prove that the thing is dead by testing and then proving your tester.
You have to take the lid off to get to the terminals to test.
You must carry out safe isolation before you take the lid off.

Haha ............ nice one .... I was very gently leading our Friend towards that trap but you beat me to it!!

 

[Brightspark2]

It can be carried out with just the MCB off yes. You don't have to do them all together.

Don't just think about a domestic setup where your more likely to do a group IR but also commercial and industrial where your less likely to do them all together.

 

[driverman]

It can be carried out with just the MCB off yes. You don't have to do them all together.

Don't just think about a domestic setup where your more likely to do a group IR but also commercial and industrial where your less likely to do them all together.

So, if your on a 3 phase Dis/ Board and you want to carry out an IR test on 1 particular circuit but without switching all circuits off, do you just lock off circuit under test? Would that conform to GN3 BS7671? I'm only asking this as I'm sat here revising 2395.
According to previous Test feedback...Many people are getting this typical question wrong.

 

[davethsparky]

I would suggest you don't need to lock off the MCB as you will obviously have isolated the whole board and locked it off and placed signs etc before you took the lid off.

On an open internet forum where anyone could be watching no sensible person will ever admit that they would even consider opening an enclosure without isolating the supply to it first.

 

[davethsparky]

Now for a slight tangent,

If you are working on a DB (eg connecting a new circuit) and you have isolated it at the mainswitch of said DB do you need to lock it off?

 

[Guitarist]

This is all well and good until your part P assessor asks you to take the lid off a shower unit to carry out a Zs test. Safe isolation? Looks great on paper doesn't it?
It's like most things in the trade, such as working at height or in an unboarded loft....All fine and dandy until you get into the real world.

 

[davethsparky]

Wait a minute! we don't have to work in unboarded lofts? I love it! 'Sorry madam its going to have to be mini trunking across the ceiling and your big plaster ceiling rose, i'm not allowed in you loft unless you get it boarded'

I can smell another catch 22 coming along though:

Can't run cables round the loft until it's boarded out
Can't get get the cables to where they need to be cos the loft's boarded out
Can't run cables round the loft until it's boarded out
Can't get get the cables to where they need to be cos the loft's boarded out
Can't run cables round the loft until it's boarded out
Can't get get the cables to where they need to be cos the loft's boarded out
Can't run cables round the loft until it's boarded out
Can't get get the cables to where they need to be cos the loft's boarded out

 

[driverman]

Wait a minute! we don't have to work in unboarded lofts? I love it! 'Sorry madam its going to have to be mini trunking across the ceiling and your big plaster ceiling rose, i'm not allowed in you loft unless you get it boarded'

I can smell another catch 22 coming along though:

Can't run cables round the loft until it's boarded out
Can't get get the cables to where they need to be cos the loft's boarded out
Can't run cables round the loft until it's boarded out
Can't get get the cables to where they need to be cos the loft's boarded out
Can't run cables round the loft until it's boarded out
Can't get get the cables to where they need to be cos the loft's boarded out
Can't run cables round the loft until it's boarded out
Can't get get the cables to where they need to be cos the loft's boarded out

Davethesparky should be called Catch22 instead me thinks!