Lift supply

[studentspark]

Need to isolate a 3 phase board to swap out a failed MCB
The board powers a lift amongst other things (its a community centre being converted) so is unoccupied at the moment.
Never had any dealing with lifts before, is there any issues, or procedures involved when shutting off power to a lift - apart form making sure nobody is in it!

Thanks

 

[DaveHerns]

Why are you being asked to do a job without proper training?

 

[bernardgreen]

As DaveH said, why are you doing this without being aware / trained / instructed about how the lift will react to a power failure.

If there is no one to provide you with the necessary information then contact the manufacturers of the lift and ask for their advice.

 

[studentspark]

I have emailed the lift manufacturers and the company who serviced the lift recently for advice, that was two days ago. Not heard anything.
I will not be doing anything I do not feel right about , but thought I would geta few opinions on here.

 

[333rocky333]

We would normally do a joint attendance with a lift engineer present.
They would normally park the lift up safely with the door open and barriered off

 

[studentspark]

Thanks 333 that sound a sensible way to go about it.

 

[333rocky333]

To be honest its no different to a power cut really, and most things spring back to life ok.
However when things go tits up or dont work after, the blame will fall on you, including accusations that the thing should be shut down in a certain way.
You do here scare stories about doors opening and people stepping into the open shaft but i think thats unlikely without a mechanical failure.

Over the years ive been acused of breaking computers, cctv all sorts of things, just for turning off an mcb accidentally in an unmarked board.
back in the early days it was quite common for a bank worker to lose about half a days work turning off there computer, we would get a rollicking, even though the worker should have regularly saved her work.

Modern lift rooms nowadays only have a little box in them, compared to the past.
weve been to power failures, yet on reinstating power the lift aint come back on, so whether theres any safety features built in, thats not for you to know.
the law requires you to do a risk assesment, so your entitled to ask for a specialist, if lifts are not your field.
You say the buildings unoccupied so the lift people may be happy for you to leave it off at the mains till they attend and check it over.

I would, if turning it off is unavoidable, take the car to the lowest point, as that is the safest.

 

[bernardgreen]

and most things spring back to life ok.

After a power cut some lifts require a manual reset sequence before the lift can be put back into service.

I would, if turning it off is unavoidable, take the car to the lowest point, as that is the safest.

Again check with the lift manufacturer, often the counter balance is heavier than the empty car and then if there was loss of brakes the counter balance would drop pulling the car to the top.

 

[333rocky333]

Again check with the lift manufacturer, often the counter balance is heavier than the empty car and then if there was loss of brakes the counter balance would drop pulling the car to the top.

Good point, never considered that, is that mainly older lifts.

 

[flameport]

Again check with the lift manufacturer, often the counter balance is heavier than the empty car and then if there was loss of brakes the counter balance would drop pulling the car to the top.

While that is a theoretical possibility with some types of lift, a loss of power does not result in the brakes being released.

 

[Steve]

Barnsley council recently put out a message on twitter saying there will be several loud bangs in the town centre that day and not to be alarmed. They were decommissioning the lifts in their old office building, which involved taking the cars to the bottom, then allowing the counter weights to simply fall to the bottom of the shaft after cutting the cables.

 

[bernardgreen]

a loss of power does not result in the brakes being released.

In theory it is :- if no power then brakes hard on and in the old days of primitive lifts that happened. In practice slamming the brakes hard on when the car in moving is not good for the cable or when the car is descending for the passengers with the potential of injuries to ankles, knees, hips and spine. Almost all braking is regenerative braking with the motor becoming a generator into a load bank. This works in an unexpected loss of power in that it will slow the car to a very low speed when the hard stop brakes can be applied.

 

[Adam_151]

Seems a lot of worry about not a lot, as said a it will be designed to remain safe under a power failure, although you do want to avoid there being anyone in it or it being mid travel for a planned event. Call it to the bottom, hold the doors open with a toolbag in the way of the break beam detector and barrier it off / place signs / have someone tell people not to use it.

You say its not yet occupied, so if the lift ends up needing a reset by the service company and is out of action for a few days, its not a big deal at this stage.

What make of board is it btw...?

 

[Tigercubrider]

If the building is undergoing a refurb, wouldn't it make sense to have the lift serviced anyway?

 

[333rocky333]

I have emailed the lift manufacturers and the company who serviced the lift recently for advice