How is that possible

Mark E Smith

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190
Location
Arkansas
Getting ready to put in a ceiling heater going to be using a 220v plug outlet on it's own circuit so before it gets here was looking over my breaker box, making sure my 220v circuit had the right size wire etc...noticed I don't have anything labeled...so...spent the day checking each breaker to label it. I thought I had every thing spread out pretty good, because you know saws and what not pull some heavy amps some times. Every thing was pretty good except one circuit...I was shocked... seems when I use my CSMS, man I got a bunch of stuff running on that circuit, when I use it that circuit it has a mini frig (2.4 cf Kenmore) plus my Dust collector, and because it's my CSMS my shop vac (csms needs both Shopvac and DC) and the CSMS itself, they are all on different plugs which is why I assumed I was spreading out the load. How is that possible to run all of that on one 20amp breaker, jeez the csms is 15 amps and the DC is also 20 amps, that alone should kill the breaker. The DC always run with every machine, but the CSMS is the only one on the same circuit with the DC. The mini frig is always on with the DC, can't change that, the shop vac I guess can be used with an extension cord to the other side of the shop. But for some reason I use this setup all the time, never had a breaker trip, can some one explain how I run four major pieces of equipment on one 20amp breaker. Granted I turn on things one at a time, but still, that's a lot of stuff.

edit: did a quick check...that's 42+ amps on a 20 amp breaker

HF Dust collector - 20 amps
Kenmore mini frig - 4 amps (guess couldn't find a plate)
Shopvac 16 gal - 7.4 amps
Dewalt DW717 - 15 amps
 
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You're assuming that 42 amps is constant, but it's likely not. It's the full load on everything, but likely no two of them are running anywhere near full load at the same time. The DC is probably loafing along at well less than the 20 amp rating, and so is the vac. As for the saw, it's only likely to draw the full 15 amps when it's actually cutting heavy stuff, near its capacity.

They'll all draw a momentary high load when starting, but the breaker is designed to handle that. Running load for all three is probably pretty close to full load on the breaker, though, so common sense would say to move at least one of the items to another circuit.
 
Thanks Jim, unfortunately the only thing I can move is the Shopvac, everything else is fixed on the one wall and every plug is on that circuit. I guess the order I turn things on seems to be saving me. I always pull the blast gate first which remotely turns on DC (Long Ranger system) then I turn on the Shopvac and finally the mitersaw, then after the cut in the reverse order. Thinking the frig is probably very low and just never hit the timing of the compressor when I was sawing. May have to have Mr Sparky out to see about putting the DC on a new dedicated breaker...
 
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