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Topic Title: Access to MCBs
Topic Summary: Training required
Created On: 07 December 2017 01:05 PM
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 07 December 2017 01:05 PM
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johno12345

Posts: 216
Joined: 22 October 2005

Hi,

I have been pulled by our HSE department, for a Schneider Isobar 4 dis board, with the door found ajar.

Inside, it has the obvious array of MCB/RCBOs, one of which is used for functional switching.

HSE have said that i need to install an additional switch, at the side of the board for the operators to use, and install locks on the doors of all dis boards to comply with the electricity at work regs

I was always of the impression that the Schneider MCBs were rated for functional switching, and that boards only had to be locked if live parts could be accessed.

Anyone got any advice?
 07 December 2017 01:41 PM
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AJJewsbury

Posts: 16095
Joined: 13 August 2003

Do the MCBs etc comply with BS EN 60898? (perhaps as well as BS EN 60947) - if so they should be suitable for use by ordinary persons (BS EN 60898 being the "Specification for circuit-breakers for overcurrent protection for household and similar installations").
- Andy.
 07 December 2017 01:56 PM
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johno12345

Posts: 216
Joined: 22 October 2005

the MCB complies with BSEN60898 and 60947, thats good to know, i wasnt aware that it was specifically noted that they were suitable for use by ordinary persons.

I guess that MCCBs to 60947-3 should be operated by persons of a certain qualification?


any thoughts on the panel door being open?


Thanks as always
 07 December 2017 01:59 PM
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mapj1

Posts: 9689
Joined: 22 July 2004

Law wise you are probably OK, but I suppose we should ask who is flipping the MCBs and why ?
Depending on what is happening there may be other reasons for wanting the door shut.

As extreme examples, if it is a few times a year for a caretaker to change a light bulb, or just every evening for a couple of weeks while the Christmas lights are in season, it is far more sensible than if, say, the circuit overloads regularly, and all and sundry including the cleaner with wet hands, are in the habit of just flicking it back on willy nilly when it goes off.
Is the box in an exposed place where visitors of unknown integrity might decide to have a play and kill the burglar alarm or something?
There is a huge difference if only known members of staff can get to it, like an office or a closed workshop, versus in an open area like a lobby.

I suspect not so much the EAW but more where it is and who is or is not trusted , may be a consideration.
After all 'training' at the level of the chap who changes the lamps is really a case of how to read the labels and flick the right one, and how to be sure the right lighting circuits have actually gone off.



Is there a risk of them switching the wrong breaker and causing all sorts of mayhem or some kind of accident ?

-------------------------
regards Mike
 07 December 2017 02:03 PM
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johno12345

Posts: 216
Joined: 22 October 2005

no danger from things being turned off in error.

its just a small power board, the reason the operator opens the panel for the MCB is to turn the gas heaters on and off, not resetting it for any sort of nusance tripping.

The MCB is rated for 20,000 operations, so thats a long time considering how often it is used.

the board is also out of the way, no visitors would likely even see it
 07 December 2017 02:10 PM
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gkenyon

Posts: 4981
Joined: 06 May 2002

Originally posted by: AJJewsbury

Do the MCBs etc comply with BS EN 60898? (perhaps as well as BS EN 60947) - if so they should be suitable for use by ordinary persons (BS EN 60898 being the "Specification for circuit-breakers for overcurrent protection for household and similar installations").

- Andy.
Only if they are in a DBO or similar, surely?

-------------------------
EUR ING Graham Kenyon CEng MIET TechIOSH
G Kenyon Technology Ltd

Web-Site: www.gkenyontech.com
 07 December 2017 02:11 PM
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gkenyon

Posts: 4981
Joined: 06 May 2002

Originally posted by: johno12345

no danger from things being turned off in error.



its just a small power board, the reason the operator opens the panel for the MCB is to turn the gas heaters on and off, not resetting it for any sort of nusance tripping.



The MCB is rated for 20,000 operations, so thats a long time considering how often it is used.



the board is also out of the way, no visitors would likely even see it

Note 5 to Table 53.4 (which is the note to the "Functional switching" column) in BS 7671:2008+A3:2015 says circuit-breakers and RCDs should not be used for frequent load switching.

-------------------------
EUR ING Graham Kenyon CEng MIET TechIOSH
G Kenyon Technology Ltd

Web-Site: www.gkenyontech.com
 07 December 2017 03:02 PM
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johno12345

Posts: 216
Joined: 22 October 2005

i have looked at my regs books, and that note isnt present, the installation is from about 2008, so would i be right to say that it complied at the time, but not to current regs?

and the door being unlocked (unlockable) isnt an issue, as the MCBs are all designed to be operated by ordinary persons?

thanks
 07 December 2017 03:46 PM
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AJJewsbury

Posts: 16095
Joined: 13 August 2003

Originally posted by: gkenyon

Originally posted by: AJJewsbury



Do the MCBs etc comply with BS EN 60898? (perhaps as well as BS EN 60947) - if so they should be suitable for use by ordinary persons (BS EN 60898 being the "Specification for circuit-breakers for overcurrent protection for household and similar installations").



- Andy.
Only if they are in a DBO or similar, surely?


They'd have to be in a suitable enclosure of course, although not necessarily a matching CU I'd suggest. You often see MCBs and RCBOs on other equipment - such as EV charge controllers, Electric boilers and caravan hookups - which are clearly intended for operation by ordinary persons. Is the OP's DB enclosure suitable? I'm not sure, but that a slightly different question to whether the MCB itself is suitable, I suggest.

Note 5 to Table 53.4 (which is the note to the "Functional switching" column) in BS 7671:2008+A3:2015 says circuit-breakers and RCDs should not be used for frequent load switching.

I'm not sure that note (5) is a flat "should not" more of a "check with the manufacturer's instructions" (which it seems that the OP has done).

- Andy.
 07 December 2017 03:53 PM
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CMK3PD

Posts: 70
Joined: 23 September 2016

It's possibly the assembly that is the issue rather than the device. If the assembly is manufactured to BSEN 61439-3 then that has been designed for operation by ordinary persons and does not require any special locking facility, in the same way your consumer unit probably just has a friction latch on it.

If it was manufactured to 61439-2, then that is deemed only suitable for skilled or instructed people and should be controlled entry either through a locked room or the enclosure itself being lockable.

Personally I'm not keen on operating protection devices as a mater of course, people become oblivious to the possible dangers of switching and may well continually try and reset a trip condition, whereas someone with knowledge is unlikely to do it more than once without further investigation taking place.

EDIT: Just read your post properly, I thought you said pulled by HSE, as in executive. If it's within your company and that is what they want I would just do it and be done. No real value in causing issues where you don't have to and as I mentioned above I would prefer a switch anyway, leave the protection to the skilled staff.
 07 December 2017 04:16 PM
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johno12345

Posts: 216
Joined: 22 October 2005

the board is to 61439-3 - so, that means its designed to be operated by ordinary persons (this is important because im being told that all boards need to be locked with padlocks)

it is internal HSE, but locking 110 odd boards isnt an insignificant task.


I dont think its ideal using the MCB as a switch, but I dont like it when im told something is a breach of regs when it isnt.


im glad I have asked here, as boards to 61439-2, which i think are panelboards with MCCBs, all came with locks in the doors.
 07 December 2017 04:48 PM
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AJJewsbury

Posts: 16095
Joined: 13 August 2003

No real value in causing issues where you don't have to

The "elves" aren't always right though - and it's not healthy for them (or us) to think they are. Time and money spent on unnecessary changes means that other things - possibly far more beneficial - aren't being done (be that thermostatic valves before the hot taps, better routine general maintenance or an extra cream cake for the workers). Worse they can occasionally demand things that if unchallenged would actually make things worse (look good on paper but overlook the practicalities). Keep them on their toes I say!

- Andy.
 07 December 2017 06:14 PM
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davezawadi

Posts: 3954
Joined: 26 June 2002

I agree Andy, they should be challenged as improper "H&S" has long been the excuse for anything. In my view everything you have said is safe enough and fully compliant with the Electricity at work Regs. They must have time on their hands, in which case further study would be a good idea to save wasting other peoples time!

-------------------------
David
BSc CEng MIET
david@ZawadiSoundAndLighting.co.uk
 07 December 2017 06:31 PM
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mapj1

Posts: 9689
Joined: 22 July 2004

The usual is to request the regulation no. they think is being breached. After all you presumably have a copy of the book they don't.
IF they would like to involve the company in additional expense over and above that required by regulation, then they should be able to justify why it is required.

Having seen the fun that ensues when a substantial board is locked by a key that has just accidentally driven home in someone's trouser back pocket, and the RCBO has just done its thing on a freezer circuit, unless locking is really needed, then there is a lot to be said for controlling access in other ways, or indeed training / trusting your staff. Maybe adding a label 'Contact electrical facilities dept extension 1234 before opening' would be more sensible in some companies.



-------------------------
regards Mike
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