Russs57
Senior Member
- Location
- Miami, Florida, USA
- Occupation
- Maintenance Engineer
So, I have a portable chiller. Two circuits, each around 450 amps, 3 phase 480. I am running parallel (portable/temporary) cables with cam lock connectors. Two cables per phase to each of the circuits. Only one cable for ground for each circuit. So a total of fourteen 4/0 cables. The cables are supplied with the chiller and an electrical contractor has run the cables. Lets call each conductor one fifty to two hundred feet in length. So I wouldn't say each circuit is the same length as one circuit is perhaps fifty feet longer. However each circuit has all cables being the same exact length. Both circuits are derived from the same circuit breaker.
Now to my question. Does it matter how the cables are laid out? By that I mean, for each circuit, do I want to run two A phases next to each other, followed by two B phases next to each other, followed by two C phases next to each, followed by one ground? All cables are as close to each other as possible and laid on concrete. They are outside in the weather for the last fifty to one hundred feet.
The reason why I ask is I'm not sharing current as equally as I would like. Connections at the supply side (crimped ring terminals bolted to breaker's bus bars with 3/8-16 bolts with belleville washers) have over heated but not outright failed (insulation is melted).
Safe to assume any current reading on the ground conductor is magnetic/inductive coupling and not a cause for concern regardless of magnitude?
I'm purposely not stating degree of current unbalance on phase conductors nor amount of current of ground conductor (all readings were done with clamp on type meter). I'd rather you guys tell me how much is too much.
Thanks in advance.
Now to my question. Does it matter how the cables are laid out? By that I mean, for each circuit, do I want to run two A phases next to each other, followed by two B phases next to each other, followed by two C phases next to each, followed by one ground? All cables are as close to each other as possible and laid on concrete. They are outside in the weather for the last fifty to one hundred feet.
The reason why I ask is I'm not sharing current as equally as I would like. Connections at the supply side (crimped ring terminals bolted to breaker's bus bars with 3/8-16 bolts with belleville washers) have over heated but not outright failed (insulation is melted).
Safe to assume any current reading on the ground conductor is magnetic/inductive coupling and not a cause for concern regardless of magnitude?
I'm purposely not stating degree of current unbalance on phase conductors nor amount of current of ground conductor (all readings were done with clamp on type meter). I'd rather you guys tell me how much is too much.
Thanks in advance.