Working in live enclosures

[industryspark]

TPN switchfuse bolted onto a busbar chamber. Bottom half (supply terminals) live and covered by the manufacturer fitted shield. Cables to be connected to the top load terminals. Some sparks i know would happily work on the top terminals even though the enclosure houses live, albiet shielded terminals.............opinions?

Regards

 

[davesparks]

That's a bit of a non-question really, why do you think the shield/guards are there in the first place?

 

[trev]

TPN switchfuse bolted onto a busbar chamber. Bottom half (supply terminals) live and covered by the manufacturer fitted shield. Cables to be connected to the top load terminals. Some sparks i know would happily work on the top terminals even though the enclosure houses live, albiet shielded terminals.............opinions?

Regards

If there is absolutely no means of isolation then sometimes we don't have any choice. I've done it as will have a lot of others on here but only as I say, when there's no other choice.

 

[Guest77]

I know of a guy who has walked through a live chamber, and another time he has touched the bars to feel which ones were overheating, sounds crazy, but it is the Truth.

 

[industryspark]

Im not saying one way is correct over another, just seeking opinions. EAWR states we shouldnt work on or close to live terminals............would working in the enclosure be classed as a breach of this if the switchfuse could easily be isolated with minimum inconvenience?

Is the shield screen there to provide protection against accidental contact or is it there to permit working in this way?

 

[trev]

Come on then Industryspark, what's your take on it?

 

[trev]

Im not saying one way is correct over another, just seeking opinions. EAWR states we shouldnt work on or close to live terminals............would working in the enclosure be classed as a breach of this if the switchfuse could easily be isolated with minimum inconvenience?

Is the shield screen there to provide protection against accidental contact or is it there to permit working in this way?

If there's a means of isolation then only a complete bloody idiot wouldn't use it.

 

[Carlosfandango]

I know we're not meant to work live, but surely we're electricians and we're Trained to work with electricity! As long as you respect it and be careful! That's my view and I'll continue to do it!

 

[industryspark]

With the fuses removed and padlock attached then i would say the risk is minimal. But, if its not unreasonable to have the supply terminals isolated too then i would have the whole isolator 'dead' on any method statement i put my name to.

Whats the risks, isolator terminals or body breaking on tightening up if old, dropping a tool down the back and it catching the live terminals ect...........unlikelly but if they can be negated, then i would.

 

[davesparks]

If there's a means of isolation then only a complete bloody idiot wouldn't use it.

Hold your horses there a minute, if the said piece of switchgear has the live side fully shielded/insulated then isolating the bits behind the shields makes no difference at all to the work.

 

[Richard Burns]

EAWR states that works should not be undertaken on or near live conductors where this may give rise to danger, if they are suitably protected then they will not give rise to danger and so live working is OK.

That said if there is a means of isolation then it should be used, take all precautions necessary to prevent exposure to danger.

 

[Andy78]

The way EAWR words it:

No person shall be engaged in any work or activity on or so near any live (uninsulated) conductor that danger may arise unless...
it is unreasonable in all the circumstances for it to be dead, and...
it is reasonable in all the circumstances for him to be at work on or near it while it is live; and ...
suitable precautions (including where necessary the provision of suitable PPE) are taken to prevent injury.







But sometimes you just need to get cracked on :smilewinkgrin:

 

[trev]

Hold your horses there a minute, if the said piece of switchgear has the live side fully shielded/insulated then isolating the bits behind the shields makes no difference at all to the work.

Not the way I read that mate. I took it to mean that the chamber can be isolated.
So far I stand by every word I've said on this one. Sometimes we have no choice but to work live but if there is a means of isolation then it should be used. No ifs or buts.

 

[davesparks]

With the fuses removed and padlock attached then i would say the risk is minimal. But, if its not unreasonable to have the supply terminals isolated too then i would have the whole isolator 'dead' on any method statement i put my name to.

Whats the risks, isolator terminals or body breaking on tightening up if old, dropping a tool down the back and it catching the live terminals ect...........unlikelly but if they can be negated, then i would.

There's no point padlocking it if you are working on it, either the handle to turn it on with will be attached to the front cover you have taken off or will be interlocked so it can't be switched on while it's open.

And of course you'll be stood right in front of it so the only way it could be switched on accidentally is if you did it. If you need to padlock an LV switch which you are working on just in case you turn it on whilst you are working on it then you may want to get some more experience before working on your own!

 

[Pete999]

Switch locked off and warning notices displayed
Mimic diagram altereed to show wor
Customer informed of intended works
Out going terminals proved dead with the appropriate GS38 test equipment
Method statement supplied
Permit to work live supplied
risk assessment supplied
2nd competent person in attendance
Barriers erected
PPE and insulated tools Supplied and used

Can't think of anything else, these arrangement are not in order

 

[industryspark]

Lol, dont jump the gun and be so presumptious Davesparks...............

The handle for ON/OFF isnt built into the door, therefore the door can be removed and the switch still operated.............this means you could throw the switch and the supply fuse bolt terminals would be live and accesible...............Admittetdly, why you would throw the handle is another question but the padlock would negate this possibility.

 

[davesparks]

Lol, dont jump the gun and be so presumptious Davesparks...............

The handle for ON/OFF isnt built into the door, therefore the door can be removed and the switch still operated.............this means you could throw the switch and the supply fuse bolt terminals would be live and accesible...............Admittetdly, why you would throw the handle is another question but the padlock would negate this possibility.

Which make and model of switchfuse is it? I don't think I've ever come across one that isn't interlocked with the cover!

 

[industryspark]

Couldnt tell you the model number but it was an old square D type one.

Im not saying either way is correct but to me this is always a grey area. In effect you have live terminals inside the enclosure your working in but they are in effect shielded (just a general plastic cover, not individual shrouding)..............as you would be working on the top terminals, the risk is low.............but, if the bottom could be isolated out of hours, then would anyone doing it the live way be breaking EAWR? Thats my query.

 

[snowhead]

How would anyone doing Domestic work fit MCB / Rcbo and connect up in a Consumer unit if it wasn't acceptable to work in an enclosure with shielded live terminals?

If in the Board the O.P is refering to there are no gaps in the shielding to drop anything in or get fingers past, then it must be O.K to work in it.

If it was one of the old MEM switches with a piece of Paxolin held in by split pins that'd be different.

The only locking off I'd be doing would be on the other end of the cable.

 

[GMES]

Right or wrong I have been doing it for many years now, it's 2nd nature to me.
I often have to install new supplies from mccb panel boards which means having to slot a mccb onto live busbar which does require you to be very careful when you can be inches from a 2000amp live busbar, but there are not many companies that would allow you to shut down an entire factory while i put a new bit of kit in.
This is not bravado just the real world, sometimes these things have to be done.

 

[bigdavs83]

Further to the domestic board example. How do you carry out your ze if you absolutely must not work live ever? Especially when you can't pull the fuse due to the DNO tag. I for one am guilty of being possibly too comfortable with live boards. Think nothing of installing new mcb's in live TPN db's. Everything is to ip2x so no stray fingers should be able to touch anything live.

 

[shanky887614]

the only live working ive done is with elv dc and some house bashing (didnt know where it was fed from)

 

[shanky887614]

Further to the domestic board example. How do you carry out your ze if you absolutely must not work live ever? Especially when you can't pull the fuse due to the DNO tag. I for one am guilty of being possibly too comfortable with live boards. Think nothing of installing new mcb's in live TPN db's. Everything is to ip2x so no stray fingers should be able to touch anything live.

the new schneider boards have a covered neutral busbar and it only engaged when you pull the plastic tab on each breaker so is about as safe as you can get

 

[Pete999]

Further to the domestic board example. How do you carry out your ze if you absolutely must not work live ever? Especially when you can't pull the fuse due to the DNO tag. I for one am guilty of being possibly too comfortable with live boards. Think nothing of installing new mcb's in live TPN db's. Everything is to ip2x so no stray fingers should be able to touch anything live.

Testing ZE is live testing mate there is a difference

 

[Andy78]

Further to the domestic board example. How do you carry out your ze if you absolutely must not work live ever? Especially when you can't pull the fuse due to the DNO tag. I for one am guilty of being possibly too comfortable with live boards. Think nothing of installing new mcb's in live TPN db's. Everything is to ip2x so no stray fingers should be able to touch anything live.

Apart from those sticky out busbar bits of course :smilewinkgrin:
This is one reason the Schneider isobar system is so good..

You raise a good point about the Ze measurement. The way I had it explained to me is that where live testing is required to be carried out, it is deemed reasonable to work live. Here's a point for debate though..... Zs values are permitted to be calculated from measured results so in theory we are all breaking the EAWR when we take a EFLI reading where live parts are exposed.......:thinking:

 

[jaypp]

This has me wondering why we all have insulated drivers etc.?:smilewinkgrin:

 

[Andy78]

This has me wondering why we all have insulated drivers etc.?:smilewinkgrin:

They're the belt in case your braces fail....

 

[bigdavs83]

Testing ZE is live testing mate there is a difference

Not sure I get your meaning unless you've misunderstood what I mean. I'm asking if we absolutely must not ever work with a live in any part of the board then how do we carry out a ZE test. Regardless if live testing is different from live working you are connecting onto a live part of the system and therefore taking a risk.

 

[bigdavs83]

Apart from those sticky out busbar bits of course :smilewinkgrin:
This is one reason the Schneider isobar system is so good..

You raise a good point about the Ze measurement. The way I had it explained to me is that where live testing is required to be carried out, it is deemed reasonable to work live. Here's a point for debate though..... Zs values are permitted to be calculated from measured results so in theory we are all breaking the EAWR when we take a EFLI reading where live parts are exposed.......:thinking:

must admit I'm with you on the Schneider/Mersin gerin boards they're a breeze to work with. The dorman smith db's are good also as long as they have the small red caps on the bus bar connections. How often are they missing tho?!

 

[Andy78]

Not sure I get your meaning unless you've misunderstood what I mean. I'm asking if we absolutely must not ever work with a live in any part of the board then how do we carry out a ZE test. Regardless if live testing is different from live working you are connecting onto a live part of the system and therefore taking a risk.

Read the wording of the EAWR.. I posted it in #12

Live testing is required therefore it is reasonable to test live and unreasonable to do so dead, precautions in place (training, competence, PPE, GS38 etc) and away you go.

 

[bigdavs83]

Fair point. Would you be happy enough carrying out a ZE on a non ip2x main switch on a mech services panel or old style db? Still a risk in my eyes

 

[davesparks]

Not a risk if you know what you are doing and treat it with respect.

And not having lost the little covers that go on the end of the test probes to make them meet gs38 helps a bit

 

[Andy78]

I'd be happy doing all sorts of things I wouldn't post about on the forum.....

 

[bigdavs83]

Aye..... It's always a risk when my supervisor is around. Goon doesn't quite cut it.

 

[industryspark]

Im sure there are many guys who've worked in live boards and enclosures ect, we've all done it to some extent. Im not inferring anyone is wrong or right. I was merely questioning the validity of doing so when we consider EAWR, namely the paragraph that Andy copied and pasted. Its a little bit of a grey area in terms of how close is close to live terminals. What we must also consider is the individual situation, i.e working in a TPN switchfuse with live incoming terminals could be very different to a domestic CU in terms of PFC PSSC ect. Also, manufactueres instructions stating boards or switches are suitable for drawing in cables whilst the board is live would be evidence of equipments suitability to do so.

I would suggest certainly some of the things on the thread that sparks have done have certainly contravened EAWR, i.e attaching mccb's onto a live busbar because the owner of the factory didnt want you to knock power off. My personal view is that there are very very few circumstances where it is unreasonable to isolate the supply hence this should be done to preserve someone's safety over inconvenience.

 

[Carlosfandango]

Further to the domestic board example. How do you carry out your ze if you absolutely must not work live ever? Especially when you can't pull the fuse due to the DNO tag. I for one am guilty of being possibly too comfortable with live boards. Think nothing of installing new mcb's in live TPN db's. Everything is to ip2x so no stray fingers should be able to touch anything live.

When I did my FICA to get my approved ticket, you had to put a plastic sheet up over the db and any exposed metal work before doing a Ze, don't we all do that on every job???

 

[Knobhead]

You call yourself “Industryspark”, what industry allows you to shut everything down to connect in to a perfectly safe switch? You wouldn’t last long on any of the plants I’ve worked on.

 

[industryspark]

Now now Tony, play nicely. Im after thoughts on the matter, not wisecracks.

 

[bigdavs83]

When I did my FICA to get my approved ticket, you had to put a plastic sheet up over the db and any exposed metal work before doing a Ze, don't we all do that on every job???

Ha ha nut!

was that cambuslang you done your FICA? I done mine around nine years ago and there were was none of that going on. Would hedge my bets and say that no one out with the training and test centres would go to this extreme.

"Hang on lad's I'll get ma sheet oot!"

 

[jaypp]

When I did my FICA to get my approved ticket, you had to put a plastic sheet up over the db and any exposed metal work before doing a Ze, don't we all do that on every job???

deleted