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#1 Posted : 30 April 2021 15:44:30(UTC)
Rank: New forum user

Can anyone provide any information on the requirement for providing separate power supplies to an evacuation lift. My understanding is that there should be two separate power supplies to the lift via different routes from  different sources.

An electrical contractor is saying that there's only one incomer supply so taking two supplies on different distribution boards wouldn't make sense because they both come from the same incomer. My logic wouuld say that each lift supply should be from a different incomer. Any guidance on this ?

#2 Posted : 30 April 2021 21:10:56(UTC)
Rank: Forum user

BS 9999 Annex G, specifies that all lifts intended for evacuation purpose must have a secondary source of power.

Where a secondary mains feed simply isn’t feasible, it is possible to use an uninterruptible power supply system or generators, or a combination of both.

BS 9999 is not legislation, but enforcement authorities will expect responsible persons to meet the safety critieria set out in any BS if they chose to utilise another standard or a bespoke one

thanks 1 user thanked Messey for this useful post.
Fox38862 on 04/05/2021(UTC)
#3 Posted : 01 May 2021 10:59:13(UTC)
Rank: Super forum user

Even if you have a duplicate incoming supply it is almost certainly going to originate from the same local HV/LV transformer in the distribution network. In this scenario, duplication of supplies in suitable fire resistant wiring, such as high performance FP, or MICC (Pyro) would be perhaps the best chance. Feed each cable from different devices at the origin, take different routes to the lift. Ensure that the duplicate supply scenario is well documented and correctly designed. Ensure that the cable route is suitably protected and fire stopped. Ensure that the supply system is designed with full selectivity, thus should the circuit protection of the first supply (either one) fail it will not cause the main DNO protection to operate. This will allow the second supply to operate to failure. I personally would be pushing for MI (Pyro) and evidence of the adequate design in the form of calculations and selectivity studies. If you understand this, great, if not please ask away. If your contractor doesn’t, then find another one who does. You might need a competent designer to do the design and someone else to oversee the installation to ensure that it is done adequately. Let me know if that is the case & I can guide you further.
thanks 2 users thanked paul.skyrme for this useful post.
peter gotch on 01/05/2021(UTC), Fox38862 on 04/05/2021(UTC)
#4 Posted : 01 May 2021 11:04:44(UTC)
Rank: Super forum user

Sorry, my phone has mangled the post! I did space it out!
thanks 1 user thanked paul.skyrme for this useful post.
peter gotch on 01/05/2021(UTC)
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