I Know:I'll Write A Letter To A Magazine And Show Myself Up!

[securespark]

I'll subtitle this thread "THE IMPORTANCE OF SAFE ISOLATION"...

In the Jul/Aug Ed. of PE, a guy writes in to slag off a poor installation. I don't think he realised how he also exposed his own poor skills at the same time.

He went to check the wiring of a house and found no cpc in the lighting.

So, without isolating the circuit, he goes to remove the cover from a flu batten. Which just so happens to be live, as the person who fitted it terminated the loop in the earth terminal of the batten....

What a bozo!

What really makes me laugh is that he discovered it was live due to his "test lamp"...could that be a neon screwdriver??....

We are trained when approaching anything made of metal that could be live to test it first with a volt stick.

Unbelievable!

 

[BS3036]

http://www.theiet.org/forums/forum/messageview.cfm?catid=205&threadid=31587&enterthread=y

 

[Adam_151]

We all get complacent to a certain extent, I wouldn't berate a guy for removing covers off a flourescent luninaire without isolating, and who hasn't waved a volt stick at something when they get the feeling something that really shouldn't be live actually is

 

[securespark]

Hmm. If I got a shock off a flu I would face a procedural investigation.

 

[plugwash]

Do you test every metalclad socket you plug anything into before touching it? every pipe? every peice of conduit? every stair banister/gaurd rail and so on?

 

[securespark]

Do you test every metalclad socket you plug anything into before touching it? every pipe? every peice of conduit? every stair banister/gaurd rail and so on?

Sockets, pipes & conduit yes.

There have been two incidents recently involving guys I know where one got a belt off a live rad, and another where a DNO's conduit was live, but the guy was saved because he was gloved up.

I know washing machine repairers who run volt sticks round the appliances before they pull them out. It is common for earth faults to render appliance casings live.

Am I the only spark so cautious?

 

[Adam_151]

Am I the only spark so cautious?

Probably (aside from sparky bird)

I suppose we all should be more cautious, but sometimes we don't, perhaps we all have different levels of risk we are comfortable with, and on top of that a different hierarchy of risks, for example I'm much more cautious when the risks involve for example stringing insects than contact with live parts (or parts made live through a fault), you might perhaps rate them the other way around?

 

[Goldberg]

Adam_151 is right - we don't all check everything all of the time.

For example, the other night I was called to an apartment that had lost power, and I approached the apartment door I heard a "crick-crick-zzzt-zzzt-crick noise behind me. Turning and seeing what appeared to be a service cupboard, I was about to insert a metal 'sqaure peg' key in the lock, but not knowing what I'd find, I volt-sticked the metal of the lock first. Happily it wasn't live, but you never know what might be behind a closed door - this time it was 'merely' a melted meter....

View media item 13137

 

[kmeeres]

Last year i was called to replace a broken washing machine with a new one.
Nothing wrong with the old one, a rat had chewed the cable which was touching the case. Dunno what happened to the earth but fuse was intact and case was live.
Totally caught me by suprise.

 

[Adam_151]

Did the DNO attend quick enough... or did you have to resort to 'emergency abstractation' to get the power on for the tenant

 

[Adam_151]

Last year i was called to replace a broken washing machine with a new one.
Nothing wrong with the old one, a rat had chewed the cable which was touching the case. Dunno what happened to the earth but fuse was intact and case was live.
Totally caught me by suprise.

What sort of laundry room has rats in? *throws up*

 

[Goldberg]

...did you have to resort to 'emergency abstractation'...

You'll never know how tempted I was.

However, because I expected the DNO to find the cause of the burnt meter to be loose screws, I didn't want to touch anything and find myself accused of loosening anything else, so I just switched off all load on the consumer ide and taped up the cupboard with a big notice.

The DNO (who shall remain nameless) came fairly quickly, and the engineer found that most of the cutout downstream terminal screws were loose, and the ones on the meter, and the ones on the consumer's 3P isolator as well.

Every single tail in and out of the meter had heat damage - the DNO engineer said that it looked like it had been burning for years.

The frustrating part of the situation was the the DNO couldn't change the meter, and the metering company couldn't remove the cut-out seal, so both had to attend to get the supply back on.

 

[RF Lighting]

I came very close once, and now check all metal work as a matter of course.

I went to a job a few years back where there was a 100A TP&N supply to a pool house.

The pool house was rotten, and was being taken down for a replacement to be built in it's place, so the supply needed to be disconnected and made safe until the new building went up.

The isolator was metalclad, and fed in 4 core SWA.

The isolator had come away from the wall due to rot, and was laid on the floor.

I went to open up the isolator door to put my meter on the supply terminals as normal before isolating and proving dead.

When the SWA had been terminated, it would seem the gland had not be fully tightened up, and as a result, the armour had come away from the gland leaving the isolator with no earth. The gland was still covered by the shroud so this was not immediately obvious.

A second fault had also occurred. The edge of the gland had cut into the yellow phase, leaving the isolator live with a 100A non-RCD supply. I got quite a nasty shock off that.

I am now well into the habit of volt sticking everything just in case.

 

[sparkyspike]

Rubber shoes work for me.

Last week I was working on a ring circuit in an occupied house. I told the owner that he would have no power in the kitchen for half an hour. I opened the breaker and taped it up. I always carry lock-off clips, but I didn't have one which fitted this breaker, so it was taped up this time. Big mistake.

10 minutes later I got an electric shock from the wiring. I go to the fuse box and the tape has been removed and the breaker closed.

I went to the owner who said - 'Oh, sorry - it was just that the Playstation wasn't working.'

I thought I had done enough to ensure my safety - but obviously not. He really didn't realise that there was a reason for the taped up breaker. I just couldn't believe it.

My fault though. STMOTSI: Safety first.

 

[Adam_151]

Anyone switching a taped up breaker on without making enquires as to why it was taped up deserves a severe yelling at at least!

I know its not the proper way to achieve safe isolation, but sometimes you have to!