UPS Cable Type

[DM2]

I'm working on a 24 VDC UPS, 1600 Amp Hour, 75Amp system.

I'm trying to find out what type of cable I need to be using.

There will be 5 trays of batteries and each tray will have a maximum current draw of 15 Amps. Each tray will be fused at 20Amps. Each tray will have 4, 100 Amp VLRA batteries.

The wiring from the UPS to the Fire Panel will be a single pair, with a maximum current of 75 Amps and will be fused at 100 Amps.

I intend to size the cable for each tray to handle 25 Amps min., and from the UPS to the Fire Panel, for 125 Amps min.

I've looked at article 700, 701, and 702 for some hints on the type of cable but can't seem to find any.

Anybody experience with UPS's and the types of cables?
Do you see anything wrong with the logic on how I intend to size the cables?

Regards,
Dan

 

[MikiBg]

Doesn't sound bad for this amount of data. Make sure that ur rectifier has internal overload protection, otherwise 100A fuses wont do the job properly. I suppose cables are not too long, so voltage drop wont be a problem. UPS manufacturers usually provide single core flexible cables for DC connections. 125A single core cable...hm, large diametar, hard to handle, maybe better 2 cables in parallel. Pay attention to final step, choosing conductor diametar. U can use low voltage AC cable data (and cable too), because DC current has same thermal effect as AC current with equal RMS. Conductor and insulation material are key factors (assuming u already took into account ambient temperature and laying conditions by 125A). Cable carrying capacity must be enough higher than nominal current of protective device. Don't u have an electrical engineer for this job? Good luck!

 

[DM2]

Thanks MikiBg,

What type of cable would you recommend running between the Battery Cabinet and the Power Supply (about 15' of cable).

Regards,
Dan Marr

"Real world Knowledge isn't dropped from a parachute in the sky but rather acquired in tiny increments from a variety of sources including panic and curiosity."

 

[MikiBg]

You're welcome!
My tip was mostly about ur second question. I would like to help u more, but since I'm in Europe, I'm not familiar with US cable types/markings and I'm thinking in MKSA system, so there's quite possibility for unnecessary misunderstanding. Besides, an exact cable type recommendation without more data or even site/equipment seeing...not a good practice. Better consult someone else. Hope you'll understand and once again...good luck!