MCB Lock Off Device

I personally don't know the answer a sparks would give, but my personal take on it is, anything that could stop you from being killed by somebody switching the MCB back on, not knowing you are working on the circuit has good to be a good thing.

 

Please refer to EAWR operational procedures Dave - thank you..

 

Hi DIYDave

I use one of these http://www.test-meter.co.uk/kewtech-kewlok-electrical-safety-lockout-padlock/

Wouldn't be without it in an industrial situation.

Kind regards

BS

 

We had a little ditty on site, and it follows thus -

''If In doubt - whip the cut-out out''

 

I do keep a few in the car, never ever used them but I keep them handy in case I ever get asked to produce them on niceic assessments, never been asked up to now! As my work is all domestic I don't worry too much but if I done commercial i'd be a bit more cautious.

 

Hi Sen

Its so easy in an industrial environment for another spark to switch on a "tripped" mcb. I always ensure I fit a proper lockoff, then they know its intentional.

Kind regards

BS

 

If I am working on a circuit for some time, in a work place with loads of people, lock of devices are never used. I will disconnect the circuit within the distribution board, and stick my magnetic "electrician at work" sign on the DB.

Far better to disconnect that try to isolate IMO.

 

Yes Baz I don't doubt that, as I said I would be much more concerned if was doing commercial/industrial work. If I am at all worried I usually slip a short length of 1mm earth wire through the lock-off holes that most mcb's have.

 

Just as a matter of interest on my first niceic assessment some years ago he asked whether I had any lock-off devices and I said yes I have, i'll get them from the car and he said no don't bother in this situation but always consider whether you need to use them. He went on to tell me about an assessment he'd done some time before, in an office I think he said, where the chap had turned off the mcb then whilst doing a test of some sort suddenly there was a bang. It turned out that the receptionist had wondered why her printer or something wasn't working, then went and looked at the d/board and found an mcb turned off, and of course turned it back on!

 

My point entirely.

Kind regards

BS

 

Hi Lec

See your point, but opening a 3 phase DB to disconnect a circuit, be it one, two or 3 phases live goes against the electricity at work regs when you can isolate and lock off in seconds.

Kind regards

BS

 

How many times do you isolate a CU or DB to add a new circuit? In reality, how often are TP DB's isolated when the cover is removed?

 

Hi Lec

I frequently replace damaged sockets and switches etc. Always isolate and lock off the circuit and prove it dead to.

Had too many close calls.

Yes, many times DB isn't isolated when adding a new circuit, but the MCB isn't there till I come to connect it.

Kind regards

BS

 

Much prefer to drop a live from an MCB than rely on a lock of device. There is nothing quite like isolation than "pulling the plug".

 

I still give my cables a short with pliers just Incase it's helped me being blown up many years ago

 

Don't matter if it's industrial, commercial or Domestic ALWAYS LOCK OFF

 

http://www.ett-ni.org/media/Safe Isolation Procedure Download.pdf

 

All these safe isolation procedures always miss one critical step in my opinion.

I believe you should verify your test lamp on the circuit you are about to isolate, rather than a proving device or known live source. The reason being, you can then be sure that the device you isolate (fuse you pull etc) is actually isolating the circuit you are working on.

In a large installation, it would be foolish to pull a fuse and test the circuit is dead - It could be dead for another reason, you may be pulling the wrong fuse.

Always test a circuit is live, and then check it is dead. If you can, operate the isolation device a couple times to prove the supply comes and goes. You know for sure you are on the correct device in this way.