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

 

[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.