screen printing > Equipment
Will the Real Electrician Please Stand Up
screenxpress:
Ok, I'm going to preface this with the concept that I am fairly well-versed (maybe just dangerous) in the basics of electrical components. I do and have run my own circuits and rewiring and attempt to do everything that would be "code" acceptable. I'm not going to create a dangerous situation.
I just recently re-ran a circuit to the work area (ok, garage), using 3 #8 and 1 #12 for 50A double breaker service. I had existing conduit to deal with so could not go much larger on the pull. Was about 125 foot pull.
To me that gives the capability of 50A of 220V equipment or 100A of 110V equipment. I'm pretty sure that's right because if everything was 110V, it would allow 50A on each leg.
Here's my dilemma.
I've got a 30A 220V dryer. I feel that safely leaves me with 20A of 220V available service or 40A of 110V available service. I have a Flash Unit drawing about 15A/110V. I'm in the south. It's hot. I need air conditioning. I can get a 220V/15A unit or a 110V/15A unit.
My math says that since the power company charges in KWH and using the formula W=V*A, the 220V (same Amps) unit would be a bit cheaper to run and more efficient. But I'm not sure there's sufficient available remaining service to allow it.
I can probably go with the 220V/15A one, which would leave me about enough power for a light bulb and no Flash (5A left). Or I can go with the 110V/15A unit and be able to run the A/C and Flash (30A/110V) and still have enough (10A) for lights, etc.
I know the basic concept for breakers is to protect where the draw is over the limit for longer periods to protect from fire. And in reality, I probably could run the 220V/15A A/C along with everything else where only brief spikes of short duration would occur when the compressor kicked in and everything would probably be okay.
Please don't suggest pulling additional service. I know that's probably the best solution but not one on the table right now, maybe later.
Opinions, Suggestions? Am I lost in my own little world?
screenxpress:
--- Quote from: screenxpress on June 14, 2011, 11:45:35 AM ---Ok, I'm going to preface this with the concept that I am fairly well-versed (maybe just dangerous) in the basics of electrical components. I do and have run my own circuits and rewiring and attempt to do everything that would be "code" acceptable. I'm not going to create a dangerous situation.
I just recently re-ran a circuit to the work area (ok, garage), using 3 #8 and 1 #12 for 50A double breaker service. I had existing conduit to deal with so could not go much larger on the pull. Was about 125 foot pull.
To me that gives the capability of 50A of 220V equipment or 100A of 110V equipment. I'm pretty sure that's right because if everything was 110V, it would allow 50A on each leg.
Here's my dilemma.
I've got a 30A 220V dryer. I feel that safely leaves me with 20A of 220V available service or 40A of 110V available service. I have a Flash Unit drawing about 15A/110V. I'm in the south. It's hot. I need air conditioning. I can get a 220V/15A unit or a 110V/15A unit.
My math says that since the power company charges in KWH and using the formula W=V*A, the 220V (same Amps) unit would be a bit cheaper to run and more efficient. But I'm not sure there's sufficient available remaining service to allow it.
I can probably go with the 220V/15A one, which would leave me about enough power for a light bulb and no Flash (5A left). Or I can go with the 110V/15A unit and be able to run the A/C and Flash (30A/110V) and still have enough (10A) for lights, etc.
I know the basic concept for breakers is to protect where the draw is over the limit for longer periods to protect from fire. And in reality, I probably could run the 220V/15A A/C along with everything else where only brief spikes of short duration would occur when the compressor kicked in and everything would probably be okay.
Please don't suggest pulling additional service. I know that's probably the best solution but not one on the table right now, maybe later.
Opinions, Suggestions? Am I lost in my own little world?
--- End quote ---
By the way, the real question here is the Air Conditioner - which way can I go?
blue moon:
It has been a while since I worked as an electrician, but let's use your math . . .
at 220V you have 50 A
30 for the dryer
7.5A for flash
7.5A for 110V AC
------------
45A that should leave you with enough juice to for a few small loads.
screenxpress:
You lost me on the 7.5 for Flash and A/C.
If plugged into a 110V circuit and tagged for 15A, how does it drop down to 7.5?
ebscreen:
For starters, you're going to get a fair bit of voltage drop from a run that long,
in undersized conduit, at hot temperatures, with parallel runs. That means higher
amp draw.
I'll leave the rest up to someone that knows more, but you can't draw 100 amps 110 on
8 gauge wire either.
Swamp cooler.
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