So cord ampacity....

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chevyx92

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VA BCH, VA
Am I doing anything wrong when I have a load of 22.4 amps, 4 wire 208 volt that is cord and plug connected and I select #8 from table 400.5(A) column "A" which is good for 35 amps to size my cord? The load connected has 2 hots neutral and ground, fed from 3 phase panel. So I choose column A here because there are 3 ccc's. Right? If sized properly then why would the 30 amp 4 wire 250v male plug give me so much trouble getting the #8 in? Am I doing something wrong here?
 
Dennis Alwon said:
If it is a balanced load on the multiwire circuit you would not need to count the neutral as a CCC.
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Ummm... considering he said it's 208 volts and a 3? panel, there will always be a current passing through the neutral if there is current passing through either or both hots, balanced load or not!
 
chevyx92 said:
If sized properly then why would the 30 amp 4 wire 250v male plug give me so much trouble getting the #8 in? Am I doing something wrong here?
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You have to strip off the insulation prior to inserting into terminal :grin:
 
Dennis Alwon said:
Why couldn't you use #10 cord? Your load is only 22.4 amps? What is the actual machine you are wiring?
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Its a commercial grade coffee maker. I took it to be a continuous appliance, considering they only have 2 of them and are always making coffee for guests and functions being held at least thats what the manager said. I guess I could be wrong for it not being continuous. What do you say?
 
mdshunk said:
Bigger coffee makers come without cords now? Do you happen to remember the brand?
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No I don't but I will find out on monday when I go back to put the breakers I had to order in. These are good size coffee makers, biggest ones I ever had to wire. Done a lot of the the ones that required a 20 amp circuit not these 4 wire 30 amperes though.
 
chevyx92 said:
Am I doing anything wrong when I have a load of 22.4 amps, 4 wire 208 volt that is cord and plug connected and I select #8 from table 400.5(A) column "A" which is good for 35 amps to size my cord?
Click to expand...
That column clearly allows #10 for your current (below 25a) and 3 CCC's.
 
chevyx92 said:
Its a commercial grade coffee maker. I took it to be a continuous appliance, considering they only have 2 of them and are always making coffee for guests and functions being held at least thats what the manager said. I guess I could be wrong for it not being continuous. What do you say?
Click to expand...
I would classity it as a noncontinuous load and use a 25 Amp OCPD per 210.20 (A).
This would allow the use of #10 Cord rated at 25 Amps as you supposed from 400.5 (A).
My reasoning would be that the load consists of 3 parts. The water heating element, surface warmer and 120v indicating lights and or timers etc.
The water heating element which draws the most current for this type of appliance will only draw for the short time when the appliance is first started, leaving a much lower current draw while warming only.
HTH
 
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