UPS for MV equipment auxiliaries - "Redundant" vs. "Dedicated"
UPS for MV equipment auxiliaries - "Redundant" vs. "Dedicated"
(OP)
My specs call for redundant UPS backup for MV equipment auxiliaries. The Contractor has provided a redundant UPS for MV equipment auxiliaries but has also connected emergency lighting to the UPS. The Client's engineers say this should be a "dedicated" UPS and have no other systems, such as emergency lighting, connected as the other systems will shorten the backup time for the MV auxiliaries. This is, of course, correct but is the Contractor compliant with the specifications (which did not use the word "dedicated")? Or could one argue that in spite of the specs failure to require "dedicated" UPS backup, good engineering practice would require the redundant UPS supplies to be dedicated for MV equipment auxiliaries only as this is critical equipment?





RE: UPS for MV equipment auxiliaries - "Redundant" vs. "Dedicated"
Does the specification (or applicable regulations) mandate a minimum time period that the UPS shall provide power? Does the contractor's solution meet that requirement, even though it's also powering the lights?
(This isn't my area, but I figured I'll kick things off with the obvious question.)
RE: UPS for MV equipment auxiliaries - "Redundant" vs. "Dedicated"
With the emergency lighting connected as well, does the UPS still last as long as specified?
If so, the client seems to be trying to get more supported time than they've paid for.
A.
RE: UPS for MV equipment auxiliaries - "Redundant" vs. "Dedicated"
RE: UPS for MV equipment auxiliaries - "Redundant" vs. "Dedicated"
If the specification did not mention that the UPS was to be dedicated, and if the UPS fulfills the required battery autonomy time, then the contractor is quite within his rights to provide the UPS as is.
Contractors are not mind readers. They either do, or do not, comply with a specification. If the client and consulting engineers have screwed the pooch, why should a contractor be to blame? If a change is required I would expect the contractor to put in a claim for a variation, and be paid for such.
RE: UPS for MV equipment auxiliaries - "Redundant" vs. "Dedicated"
RE: UPS for MV equipment auxiliaries - "Redundant" vs. "Dedicated"
RE: UPS for MV equipment auxiliaries - "Redundant" vs. "Dedicated"
Yes; redundancy is defined as "unnecessary" but a UPS is only unnecessary while prime power is being supplied. I believe my Client has defined "redundant" as "additional" and this is in error. The Contractor has now provided three additional, dedicated UPS's to meet the Client's demands and has submitted a Variation request.
RE: UPS for MV equipment auxiliaries - "Redundant" vs. "Dedicated"
In any event, a simple one-line or block diagram of the desired system is usually a good idea.
RE: UPS for MV equipment auxiliaries - "Redundant" vs. "Dedicated"
duplexed system [ENG] A system with two distinct and separate sets of facilities, each of which is capable of assuming the system function while the other assumes a standby status. Also known as redundant system.