Is there a tool to permanently lock MCB in On position?

[veedee]

I've got a modern mk metal consumer unit with 10 mcb's

I don't want anyone to toggle/switch off the mcb's as they power some devices that always need to be kept on

Is there a tool i can purchase to keep the mcb in the 'on' position until i choose otherwise?

 

[EddieM]

If you could do that, you'd be negating any overload protection the MCB offers.

 

[ericmark]

There is one to lock off, clearly it would present a danger if locked on, but in the main the lever even if held on will not stop the MCB from tripping, but MCB's are not switches as such, the normal is to have a lockable lid or cover, to stop tampering, and in the main it is to stop ordinary persons from resetting the MCB when it trips so the electrical department is aware of trips so they can investigate why.

I had an IT department who wanted an uninterrupted supply. They were told if they wanted to be sure not switched off, do it with battery back up, if your not willing to install battery back up, then clearly not a critical supply.

There are health service 13 amp plugs with no fuse, where loss of supply could mean death, but other than that to try to disable a safety system is clearly dangerous.

 

[Notch7]

Put a cupboard over the CU and put a lock on it.

 

[ericmark]

There are lock off and lock on adaptors. But it does depend on the make of the MCB,

If you could do that, you'd be negating any overload protection the MCB offers.

Depends on the make, but all I have used you can't defeat the tripping mechanism by hold the lever on. With this on this MCB it could lock on or off, but does depend on MCB design and in real terms all it does is show anyone that the MCB is on or off intentionally as those little wires could soon be ripped off.

This one with a screw which clamps the lever would be harder to remove, the lock prevents access to the screw, but since a screwdriver is a tool don't really need the lock.

Because to reset when lever is held you need to switch off and on again, it means should it trip no one but key holder can reset it. For essential supplies using the lock can result in the reverse to what was intended.

 

[JohnD]

Why are you expecting people to tamper with the supply?

 

[Mottie]

A blob of superglue.

 

[SUNRAY]

There are health service 13 amp plugs with no fuse, where loss of supply could mean death, but other than that to try to disable a safety system is clearly dangerous.

I came across this a couple of weeks ago in A&E:

The other end was a line of 4 metal clad DSO's which only appeared to be held together with coupler/bushes and just one fan plugged in. Seems like an abuse of the concession to me.

 

[SUNRAY]

As others have said use a lockable lid/cover/cupboard
The only other sensible alternative is to replace the MCB with a fuse which will deter casual flicking off. It worked a dream where we did this for a small radial which powered 2 printers and a server where the occupants insisted on turning off supplies as they left their offices at night.

Each office used to have a switch by the door to isolate the ring final but some numpty inspector insisted it was contrary to regs and got the gob to put it right, the procedure then was they had a different lock winth handle fitted to the riser in the hall containing the dist board and all of it was left unlocked

 

[ericmark]

K8041s LOCKING DEVICE FOR USE WHEN LOCKING A SENTRY MCB, RCBO, RCD OR SWITCH DISCONNECTOR IN EITHER THE ON OR OFF POSITION.
K5593s BARREL LOCK AND KEY KIT SUITABLE FOR SECURING ‘K’ SERIES SENTRY CONSUMER UNIT LIDS.ONLY SUITABLE FOR HYBRID AND INSULATED Consumer units.
Sorry about caps, was copy and paste from MK PDF.

Problem is MK stuff is obsolete so not sure if you can get it any more.

 

[SUNRAY]

View attachment 208033 K8041s LOCKING DEVICE FOR USE WHEN LOCKING A SENTRY MCB, RCBO, RCD OR SWITCH DISCONNECTOR IN EITHER THE ON OR OFF POSITION.
K5593s BARREL LOCK AND KEY KIT SUITABLE FOR SECURING ‘K’ SERIES SENTRY CONSUMER UNIT LIDS.ONLY SUITABLE FOR HYBRID AND INSULATED Consumer units.
Sorry about caps, was copy and paste from MK PDF.

Problem is MK stuff is obsolete so not sure if you can get it any more.

I sat there looking at the picture trying to work out how those 2 items were supposed to fit togeter. A case of where a picture doesn't paint a thousand words

 

[JohnW2]

If you could do that, you'd be negating any overload protection the MCB offers.

Whilst I certainly don't think that the proposed idea is something that should be done, unless there is some other way of isolating the whole circuit (because it would prevent manual switching off of the circuit, e.g. in an emergency), I don't think what you say is actually true - i.e., I think that an MCB will operate ('trip') in response to overcurrent even if the levellever is 'held up'.

Kind Regards, John
Edit: typo corrected

 

[aptsys]

If you could do that, you'd be negating any overload protection the MCB offers.

That's incorrect. The MCB will always internally trip hence why it is commonplace to lock MCBs in certain circumstances.

 

[JohnW2]

That's incorrect. The MCB will always internally trip hence why it is commonplace to lock MCBs in certain circumstances.

Indeed - but, as I said, I can't see that locking it 'on' would be safe practice unless there were some other means of at least 'de-energising' (if not 'isolating') the circuit - and the existence of such an 'other means' would presumably undermine any perceived reason for locking the MCB on, wouldn't it?

Kind Regards, John

 

[EddieM]

That's incorrect. The MCB will always internally trip hence why it is commonplace to lock MCBs in certain circumstances.

I know you can't via the switch, but I assumed, perhaps incorrectly the OP wanted to prevent the MCB from operating, which is potentially dangerous. Hence "If you could do that"