Nephilim said:
ALso wolf if you don't mind checking my math
I have 4x 12x1.2kW
dimmer packs - 48x1.2kW or 57.6kW
divide by 120V supply (single-phase supply to each
dimmer, at least as far as I can tell that's the case) gives me 480A or 120A per
dimmer.
However, each
dimmer only has a 60A
breaker in the
distro panel. Sooo.... what's my safe load here? We've been sticking to 575W or less per
channel, but even then that's pushing it, isn't it? Yet I've never had one of these breakers trip.
If a
breaker takes up more than one 'slot' in the panel, does that make it a two
phase or three
phase breaker, or just a bigger
breaker? Because these packs may be getting 3
phase after all. Or i'm just really confused. I wish I could open that panel up myself. But I can't. It would REALLY help if there was a wiring diagram on the door like there's supposed to be.
Hiya Nephillim,
If a
breaker in a panel ties up more than one slot in a panel--it could be a two pole or three pole
breaker (pole=
phase). It all depends on the breaker--some wide slot breakers are single pole, some are two pole, some are three pole--depends on the
breaker and the panel. So its impossible for me to say what it is. You NEVER want to open up a
breaker panel that is live.
For your math--you have 48 1.2kW dimmers. At full
power on max loads that is 57.6kW and well over 400 amps of draw...but again how often do you pull full max loads on all your dimmers at once? Probably never.
divide by 120V supply (single-phase supply to each dimmer, at least as far as I can tell that's the case) gives me 480A or 120A per dimmer.
Actually each 1.2kW
dimmer pulls "roughly" 12 amps at max load. In reality is it less since 100watts ia 0.837 amps typically...but as I said 1amp = 100watts is a good rule of thumb when calculating estimates. In a 12x1.2 rack at full load on each
dimmer, you can have a maximum amperage draw under 144amps...divide that by the number of phases feeding your dimmers--2 or 3, and you can figure out the "safe" amperage service you need to operate at FULL. So on a 3
phase service to
cover 144 amps--each of those 3 legs needs to be able to supply 48 amps. (144 amps divided by 3 legs of
power = 48). So a 60amp 3
phase service per
dimmer 12-pack works fine and is safe. If this was a single
phase 60amp service--you exceed the 60 amps because (follow along with the math here) if you have 144amps (roughly) and divide that by TWO legs of
power in a single
phase service, you have 72amps each
leg needs to provide for max load. Quick way to find out whether you have single or 3
phase dimmers is to look for the number of large
power cables feeding the packs--if you have 4 cables that would be single
phase (2 legs, a
ground and a
neutral)..if you have 5 cables that would be 3phase (3 legs, a
ground and a
neutral). Solook in theback of your pack and see what the number of cables are feeding the
power to your packs. If you have one BIG
multi-cable..only way to find out is to open up the
dimmer pack and look really to be sure. (DO NOT DO THIS.)
You should keep in mind that whatever you draw in amperage matters to what you have attached. A 1.2kW
dimmer does NOT automatically pull 1.2kW when you go to full....it pulls what you have on it. If you only have 575w
fixture on a 1.2kW
dimmer you are only going to pull 575w when that
dimmer is at full. If you had a 575fixture and a 150watt Inkie on the same dimmer--you are then pulling 575w + 150watts for a total of 725watts at around 7 amps. If you have NO
fixture on that dimmer--you pull NOTHING even if you
send that
channel to FULL.
That help ya?
-wolf [/b]