sundance-communications.com/forum Forums Wiring - Telecom Carriers - Trunks & Services T1's, CSU's and DSU's How many Amps????

Hello Experts
I have a quick question. The facility is providing us 40 amps of current for our equipment.
I = 40 amp
Now my question is that how they measure that 40 amps? Does it measure according to the usage, i.e how we get billed on our house equipment from electric company or is it more like of according to our equipment requirement.
For example; if system A and B both are 40 Amps, can they still be functional at a facility thats providing 40 amps only to run these 2 equipment simultaneously or would I need to have 80 amps?
Please guide.
Thanks

You have a total capacity of 40 to 120 amps available for use, depending upon the voltage you are receiving and the number of phases. If metered, you will be billed according to actual usage, which is measured in KwH (thousand watts per hour). My question is are we talking about commercial AC power?

Watts are more commonly understood by the general public, assuming you are talking about AC power. To determine the wattage available, multiply the amperage by the voltage (typically 208 in commercial or 240 in residential). Example: Commercial 208 volts X 40 amps = 8,320 watts. In a 120 volt situation, you end up with two (single-phase) or three (three-phase) separate 40 amp circuits, each capable of providing 4,800 watts. That's a bit of an unusual configuration for AC power in the phone business.

I understand this stuff and my examples look as clear as mud to me too.

If you are talking about DC or low voltages, then please disregard what I have posted because it's completely different. Let us know more detail and we can give you an answer that won't leave your head spinning.

My wildest guess would be they are providing 2 dedicated 20 amp circuits.

Only you know if this is more than sufficient, perhaps posting what you will be installing, would provide a clearer assesment.

~n

Have you considered asking the facility providers for clarification? All we can do is guess and I sure wouldn't make a business decision based upon a guess...
Mike

The facility is providing us 40 amps of current for our equipment.

Don't know why you are having a problem with this. I agree with Rusty, most likely they are simply providing two 20A/120 volt dedicated circuits or the equivalent thereof.

How is it measured? When the breaker trips you have exceeded your capacity. You should not load a circuit more than 80% continuously which would limit you to 16A per circuit.

Obviously if you have a total of 40A max you cannot draw 80A, at least not for very long.

I think you are looking at this backwards anyway. What is the nameplate power requirements for your equipment- 120? 240? VA or current draw?

-Hal

Bear in mind that the nameplate power requirements for equipment often are higher, sometimes much higher, than what the equipment actually uses.

For about $25 you can get a "kill-a-watt" meter that will tell you how much power your equipment is actually using.

Bear in mind that the nameplate power requirements for equipment often are higher, sometimes much higher, than what the equipment actually uses.

This is an old thread Brian... and please complete your profile.

As to what you recommend, if someone is going to design or specify a branch circuit capacity for specific equipment the nameplate ratings of the equipment MUST ALWAYS be used as a basis for calculations. That's the requirement. Ratings were put there for a reason by the manufacturer, not so somebody will second guess what the equipment draws.

-Hal

I realized it was an old thread after I posted.

If you're talking about computer equipment, just because some IT geek installed a 500W power supply DOES NOT mean that the equipment will actually draw that much (or that it actually needed a 500W power supply)--a situation I've seen many times. (Apparently, some of them think that a bigger power supply will make their computer go faster, or something).

By the way, the nameplate rating on a 250W ATX power supply is 7 amps @ 115V.

If you size according to nameplate ratings, you can put at most two such power supplies on a 15-amp circuit. If you assume that the nameplate rating is being drawn at all times, then the 14 amp combined load exceeds the 12 amps that 80% rule allows you, so make it one 15 amp circuit per power supply.

Know of any data centers that do it this way? The last one I saw didn't.