Is under voltage release a requirement on dist boards feeding it equipment ?

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Regards

Martyn.

Only a mediocre person is always at their best



www.electrical contractors uk.com

"it" = "Information Technology" or "Isolated from Earth"?

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Eur Ing Graham Kenyon CEng MIET

"it" = "Information Technology... Sorry

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Regards

Martyn.

Only a mediocre person is always at their best



www.electrical contractors uk.com

Not normally, but I suppose it could be a customer requirement.

Normally voltage regulation is a job for the UPS, not the DB. A lot of common UPSs are capable of voltage "boost" (or trim) - effectively auto changing a tap on a transformer - so continuing to use mains rather than using up battery power - so if the DB is upstream of such a UPS, it could be preferable to let low voltages through.

- Andy.

You need to assess the impact of undervoltage creating harmul effects on other equipment. other services or on the supply - 331.1

You then need to assess if a reduction of voltage could cause danger - and if you are satisfied no danger exists but you need to protect the equipment from damage you need to consult with the relevant person what is suitable - 445 et seq.

If you decide to do it, refer back to 445 et seq as advised bt 535.

In the vast majority of cases the answer is no, you don't need undervoltage release. I've seen some truly catastrophic losses caused by people deciding that the comms room needs and e stop and arranging that via a contactor rather than a trip circuit wired via the protecticve circuit breaker. No one notices the problem, until a brown out drops out the contactor and the whole lot goes down the tubes.

If this relates to that busbar job you mentioned in another thread, then most certainly, you wouldn't want undervoltage release. You may just consider both undervoltage and over voltage protection at the desk power bars (usually specified in conjunction with delayed re starting).

You may get undervoltage protection by default if you operate via line interactive UPS - at the end of the battery autonomy, the invertor will shut down when it can no longer maintain specified output parameters.

You would almost certainly not want the type of coarse undervoltage protection associated with contactors or shunt trips at a dist board level.

What does the brief say ? -

Regards

OMS

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Failure is always an option

Not related but similar.




Your smiley is far to appropriate! I'm sure I could just supply a expresso machine with the spec I have!

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Regards

Martyn.

Only a mediocre person is always at their best



www.electrical contractors uk.com

LoL - OK, one of those jobs then

I guess the starting point is what are you trying to protect from what - be that a danger, an inconvenience or a total loss of capability or service.

Regards

OMS

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Failure is always an option

or your wallet from a customer who thinks lots of extras should be done for free as he thinks they're "in the regs" or "standard practice"?
- Andy.

Which is why you need a design brief, or an appointment to develop that brief, with the relevant adjustment for output design deliverables defined in the fee offer - and if D&B, the cost to reflect the developed design solution -

What you exclude, is often more important than what you include, in any offer

Regards

OMS

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Failure is always an option