Emergency lighting question

[SLIPSHOD & SLAPDASH]

Proteus fire alarm switch fuses in red (or mini DB what ever they call them) come with a mcb lockout (to lock on the mcb) Dont know why as you can still flick the main switch off.

If you wedge or lock a breaker on, it will still trip off when it should,ie overload. Thats part of the various BS's

 

[m4tty]

Definitely not good practice but no point either as it'll still trip lol

 

[steptoe]

emergency switching?

 

[batty]

I agree with Manator not good to lock MCB's on and why should anybody want too anyway its just not right.

 

[Paultrim]

It's not an illegal practice and they do operate under fault conditions. So, for example if we isolate the emergency lighting circuit then we are removing a safety circuit and therefore the property/premises should not be occupied unless alternative sources are supplied for emergency lighting. The use of MCB locks should be used in conjunction with suitable isolation procedures. Our clients who use these, do so under supervision of competent electrical engineers and so if this circuit requires isolation then it's done so through proper isolation procedures, I.e isolation of the DB to allow for further inspection of the cause of fault, not just isolation of one circuit. All work is carried out by the electrical engineers not bodgit & scarpit. No unauthorised persons are allowed near a fuse board!

 

[Zeespark]

Paul, we are talking about locking an MCB in an energised position, which in My view is a hanging offence, not locking off for isolation which decent sparkies do.

AndyGuinness

 

[NozSpark]

Paul, we are talking about locking an MCB in an energised position, which in My view is a hanging offence, not locking off for isolation which decent sparkies do.AndyGuinness

It'll still trip though Andy, so it's not quite that bad

 

[kme]

It's not an illegal practice and they do operate under fault conditions. So, for example if we isolate the emergency lighting circuit then we are removing a safety circuit and therefore the property/premises should not be occupied unless alternative sources are supplied for emergency lighting. The use of MCB locks should be used in conjunction with suitable isolation procedures. Our clients who use these, do so under supervision of competent electrical engineers and so if this circuit requires isolation then it's done so through proper isolation procedures, I.e isolation of the DB to allow for further inspection of the cause of fault, not just isolation of one circuit. All work is carried out by the electrical engineers not bodgit & scarpit. No unauthorised persons are allowed near a fuse board!

I think they may be a slight confusion here. I know of the red fire switches with the lock "on" (snakehips - you know where there is one of these too, don`t you? bottom of the stairs? LHS? ).

The confusion is this Paultrim. You appear to have gone from locking ON to locking OFF in the same post - but if you lock the em. lighting off, but the ordinary lighting is still energised, then you`ve got a right royal cork-up in the design of the em. lighting. However - if you have a circuit which (properly) supplies local lighting & em lighting, then the premises can`t be used "normally", as their isn`t any lighting any more.

I know the MCBs will trip, even if "locked on". That doesn`t make it a good idea though!

 

[Paultrim]

Yep there is the confusion, the emergency lighting circuit and general working lights are on the same circuit, hence the necessity to ensure they remain energised at all times, although they go through their own designated test switches and functional switches for lighting circuits, the lock-on is to prevent non electrical personnel (unauthorised) isolating the circuit for any reason(obviousley under fault the MCB can still operate)

I must add...tho a little late in the day that I would never lock-on any other circuit/isolating device etc as stated in the regs. I use EN60204 and EN418 frequently as well as 7671 and so I understand lock-OFF procedures and the needs and requirements for local ISOLATION.

 

[kme]

Now that does raise an interesting problem.

If a client sees / hears / smells a problem with an unswitched light fitting / emergency light fitting / switch; what the hell are they supposed to DO about it? Call you?

If I had a premises where this had been done, I would be livid.

There MUST be a way for the circuit to be safely de-energised in the event of a prospective or actual problem - without hunting round for some poxy key, FFS.

Suppose a switchbank is arcing. You can hear it when you walk past, and its got a little curl of smoke coming out. WTF are they supposed to DO about itbad day explode

MCBs are not designed as "technical only" controls.......me not like that one little bit.

 

[professional]

The last time I saw this practice I wanted to castrate the person who had done it, never ever ever use a lockout kit to lock any mcb in the on position.

The last time I took the 2391 practical exam, a local contracting genius did all of his live testing with the rig main isolator locked in the "on" position.

The assessor let him carry on as they have the ability to shut down all of the rigs from various points in the workshop then, after 35 minutes of totally mental activity he was carefully led to one side and told he had failed.

After he had left the building we all had a damned good laugh .... this guy was the QS for a large contractors ROTFWL

 

[wozz]

After he had left the building we all had a damned good laugh .... this guy was the QS for a large contractors ROTFWL

Seems sensible to have a QS for a large contractor without 2391, thought that was why the course was designed?!

 

[SLIPSHOD & SLAPDASH]

Here is a link to the Proteus switchgear Proteus - Products . The pic does not show the lock-on(normally used as a lock-off) device but it does mention.......

Key Features List

Both isolator and MCB can be physically locked in ON position using devices supplied Padlocks are not supplied

 

[Sidewinder]

paultrim,

I think you need to consider several different scenarios, I don't think that it can be categorically proved that the practice of locking "on" MCB's is illegal, I don't like it.

I would prefer that the whole DB is locked to prevent unauthorised access completely if it is that important to control switching actions in the premises, think hospital wards, operting theatres etc. with on site competent persons & SAP's etc.

In an "unsupervised" location such as a small shop, say I believe that it should not be done on any circuit except, perhaps, the fire alarms, with a secondary being perhaps the security alarms.

We could discuss in detail circuits that need to be locked on for days, however, I suspect that many of these will be on premises with their own competent persons.

Anyway in the event of a fire you just hit the break glass and leave the premises anyway!

 

[NozSpark]

Here is a link to the Proteus switchgear Proteus - Products . The pic does not show the lock-on(normally used as a lock-off) device but it does mention.......Key Features List

Both isolator and MCB can be physically locked in ON position using devices supplied Padlocks are not supplied

I don't know which I dislike the most

The fact that it's lockable "on", or that it's Proteus:C