Electrical Supplies To Lifts

You need to know if it an evacuation lift, or, a general use lift that will fail if the supply cuts out.

(from memory, check it is still right) If an evacuation lift, it gets complicated in that it must have two independant supplies - the main, usual supply, then one for back up if the main supply fails. I understand that the second supply could be batteries, or a generator, or, if from the 'street/public supply' should be from a separate transformer, along with its own separate secondary supply DB (which can contain other 'life saving ancillaries' supplies.)

As for power requirement, the ones I've done are quite small, typically 32A 3 phase and neutral, SWA from the DB to where the motors sit, then a suitable isolator, from where the Lift Installers take their feed.

I havce absolutely no idea as to the actual final specs as of yet. Although not being responsible for the project other than for a supply I would not be a fan of having an evacuation facility via lift. Am thinking something like the weight of say, 4 people at a time but again, I have no idea as to what quotations or specifications exist at this juncture. Am thinking a Type C or D OPD due to intermittantant motor loads?

whjohnson said:

Am thinking something like the weight of say, 4 people at a time but again, I have no idea as to what quotations or specifications exist at this juncture. Am thinking a Type C or D OPD due to intermittantant motor loads?

Thats sounds quite small, so a 32 amp 3PN supply should cover it, though, of course, check the specs before buying any cable. Calculate the cable to allow for a D type circuit breaker, but a C type has been usual for the small shop lifts I've fitted in the past.

Oh, I also remember one Lift Manufacturer wanted two supplies, one for the lift workings, and another just for the lighting.

Thanks for your input.

I think the principle driver for installing a lift is to provide disabled access, so maybe 2 wheelchairs with accompanying adults, so 4 people max. It is also possible that the lift may be used to transport light goods such as stock for the upstiars public bar, so small packs of mixers etc.

It is all quite vague at present with nothing firmed up.

BS EN 81‑20:2020 says very little about the supply.

5.10

The lift shall be considered as a whole, in the same way as a machine with its built-in electrical
equipment.

NOTE The national requirements relating to electricity supply circuits apply as far as the input terminals of
the switches. They apply to the whole lighting and socket outlet circuits of the machine room and the pulley room.

5.10.1.1.2 The electrical equipment of the lift shall comply with the requirements of
EN 60204-1:2006 as referenced in the clauses of this standard.

So it would seem that you treat it like any other machine.

Just like any other installtion covered by BS 7671 110.1.1 the installation needs to be designed in accordance with Regulation 132.1.

I would suggest that the design is not a job for an ordinary electrician but a person who has a good knowledge of the requirements for lifts. The LV installtion normally stops at the lift controller. As has already been said if the lift is one used for a safety service such as a fire fighters lift, escape lift or special hospital lift then BS 7671 Chapter 56 will need to be complied with in addition to all the other general rules. There are other British Standards that will need to be complied with but top of the list in BS 8519.

As Chris says the BS EN 81 standards for the lift wil need to be complied with depending on the intended use of the lift. The standard for evacuation lifts, BS EN 81-76 is only a draft IK believe at the moment so the lift designer will work to this if required. The completed lift installation will ned to be inspected by a lift inspector before being put in to service. 

If this is a safety service lift the intended electrical design will need to be submitted to the Fire Engineer for the building in the form of a Technical Submittal for approval to ensure it complies with the fire strategy for the building. 

JP

alanblaby said:

If an evacuation lift, it gets complicated in that it must have two independant supplies - the main, usual supply, then one for back up if the main supply fails.

John Peckham said:

The standard for evacuation lifts, BS EN 81-76 is only a draft IK believe at the moment

BS EN 81-76 was published in July last year.

The whole thing seems to be a BSI/EN-fest.

Yes, with one exception, an evacuation lift needs a secondary power supply. The salient point is C.12 of BS 81-76:2025: It shall be instructed that the secondary power supply is effectively independent from the building’s normal power supply.

It needs to be powerful enough, etc. then it says, NOTE The electrical source of a secondary power supply is described in HD 60364-5-56:2018, 560.6.

Good luck!

As I previously stated, I don't want anything to do with the actual lift installation, but merey to provide an adequate and correctly rated supply to the destination isolator. Whatever leaves the isolator is something for which I wish to have no responsibility for. Am guessing that the lift company will provide and be responsible for the complete package after the supply isiolator, including the actual lift,l ancillaries and all other compliance issues.

At the moment there is no information to go on and this project has been rumbling on  for a few years now due to funding issues. As for escape routes etc, I see no reason to involve the use of a lift at all. There are 4 staircases leaving the main hall for that purpose and are wholly adequate, so I don't foresee any need for any safety/building evacuation measures to include the use of a electric lift.

Unaccompanied wheelchair egress?

  - Andy.

Or, as common in smaller buildings without a lift, a fire protected refuge by the stairwell. There are plenty of 'Do not use this lift in case of fire ' installations in all sorts of buildings where the effort of a second supply plus the other design factors in terms of construction materials and fire zones would make it impractical to have any lift at all otherwise.

Note that there seem to be some changes coming,  at least for residential buildings in respect of evacuation, - its not my expertise at all, but this article looks relevant- especially the notes about internal dimensions and fire protected  supplies.

https://www.cundall.com/ideas/blog/bs99912024-new-evacuation-lift-requirements-for-fire-safety-in-residential-buildings

What is very important is that everyone is on the same page as to what the actual strategy is going to be, long before committing to the design, and certainly before actually starting.

Changing it mid-stream to be more complex is not generally possible otherwise.
Mike.