Sounds reasonable. Please tell me he is not asking for a 500 MCM to go into each conduit.Originally posted by 1madison: I think he might be confusing the equipment grounding conductor with the GEC.
Good point. If the calculated load is more than 3800 amps, or if there is no calculation, or if the plan is to take advantage of all 4000 amps of the equipment's rating, then you need either one more conduit or to replace the 500's with 600's.Originally posted by roger: I think the EE might want to look at his service entrance conductor ampacity again too.
Actually with 10 sets of 500 the OCP will have to be 3800 or less regardless of the load.Originally posted by charlie b:
Good point. If the calculated load is more than 3800 amps, or if there is no calculation, or if the plan is to take advantage of all 4000 amps of the equipment's rating, then you need either one more conduit or to replace the 500's with 600's.Originally posted by roger: I think the EE might want to look at his service entrance conductor ampacity again too.
Person 2:The sky is blue.
I wasn't talking about the OCP. I was talking about the ampacity of the conductors. If the calculated load is under 3800, then you can use 10 sets of 500 MCM copper.No, you are wrong, the grass is green.
No, not with 4000 amp service, had he said a 3,800 amp service than we could agree.Originally posted by charlie b:
I wasn't talking about the OCP. I was talking about the ampacity of the conductors. If the calculated load is under 3800, then you can use 10 sets of 500 MCM copper.
That does not disagree with what I said in my first post:Originally posted by iwire:10 sets of 500 copper does not equal a 4000 amp service which IMO is what Roger was getting at.
If you know nothing about the load, if you are just saying "4000 amp service," then you need more copper.Originally posted by charlie b: If the calculated load is more than 3800 amps, or if there is no calculation, or if the plan is to take advantage of all 4000 amps of the equipment's rating, then you need either one more conduit or to replace the 500's with 600's.
4000 amp rated service equipment rarely comes with less than a 4000 amp OCP.If the calculated load is more than 3800 amps, or if there is no calculation, or if the plan is to take advantage of all 4000 amps of the equipment's rating, then you need either one more conduit or to replace the 500's with 600's.
Actually in my world I sometimes disagree with that.Originally posted by charlie b:
I also said that you pick the copper before you pick the OCP. I trust you are not disagreeing with that?
Hi Roger, I was also thinking of 240.4(C) in my first post, by my third post I realized 230.90(A) may be more appropriate but the result is much the same.Originally posted by roger:
Charlie, Bob knows me pretty well, I was hinting at 240.4(C)
Bob, I agree. Add a set or increase the conductor size.Typically (at least from this electrician's experience) a '4000 amp service' is a service with a single 4000 amp OCP.
Regardless of the load being 1 amp or 4000 amps ten 500 kcmil CU service conductors can not be protected by a single 4000 amp OCPD.
Sounds to me like he's confused about the main bonding jumper. This would be sized for 12.5% of the service entrance phase conductors.Originally posted by 1madison:
GEC from MDS to cold water POE. EE says use 1-500 kcm.I think he might be confusing the equipment grounding conductor with the GEC.
That was not my intent, and yes I do see why you would question that. I knew that you could not "biggie size" the OCP if the OCP is over 800 amps. We are not disagreeing on anything here, as I was talking about conductors and not OCPs. That was the point of my "blue versus green" analogy.Originally posted by iwire: IMO, whatever it was you where trying to say came out sounding like a 4000 amp OCP protecting ten 500 kcmil CU would be acceptable if the load was less than 3,800 amps. Can you see why I would question that?