Bonding jumper for cable tray being used as EGC?

[borracho.del.pueblo]

I'm being told that bonding jumpers are unnecessary for the cable tray I'm quoting. - Legrand Cablofil 09-6A12C-S144-36 (Cross sectional area of 1in² ) The table at NEC article 392.60 specifies a 1200A maximum for that area of aluminum tray. This maximum ampere rating appears to be the maximum of any individual breaker, fuse, or protective relay that is protecting a circuit run from the tray. After asking around a bit it seems that some run a separate EGC and bond each piece of tray/connectors using something similar to a Eaton 9A-2130. Would you guys run a separate EGC or use the tray as EGC as long as it is within limitations?

 

[coop3339]

I would run a seperate ground that way you are safe. You could just bond it to the tray in the beginning and on each side of expansion joints. I saw a roof fire caused by a cable tray in a solar system. It was the AC conductors that caused the problem. There was a ground fault to the tray and one of the couplings was loose. This created a resistance so not enough fault current could flow to trip the OCP. The tray melted and ultimately caught some leaves then the roof on fire.

 

[petersonra]

If the cable tray is listed for use as a equipment grounding conductor, I don't see any reason to run a separate wire type equipment grounding conductor.

I don't believe incompetent electricians are a good enough reason to worry about a perfectly good product. If they can't install it properly they shouldn't be electricians.

 

[Fred B]

Might want to review section 390.60(C) regarding bonding and sections that may or not may be continuous or connected together with approved methods from mfg. guidance.

 

[Jpflex]

Might want to review section 390.60(C) regarding bonding and sections that may or not may be continuous or connected together with approved methods from mfg. guidance.

I have this similar thing going on at my job. Cable trays are holding SOOW cords from a control trailer with starters to crusher motors but are not continuous and are in sections away from each other. I was thinking of running an outside EGC between cable trays based on the largest size breaker feeding the largest conductor within the cable trays 250.122

 

[petersonra]

I have this similar thing going on at my job. Cable trays are holding SOOW cords from a control trailer with starters to crusher motors but are not continuous and are in sections away from each other. I was thinking of running an outside EGC between cable trays based on the largest size breaker feeding the largest conductor within the cable trays 250.122

What would be the point if the cable tray is suitable to use as an egc? Just bond the cable tray sections together which is required anyway.

 

[Jpflex]

What would be the point if the cable tray is suitable to use as an egc? Just bond the cable tray sections together which is required anyway.

I’m thinking that the cable trays used by our company being used at a mine )which is not under NEC jurisdiction) may not be listed trays?

Also bonding the trays together is what I mentioned in the post you commented on but the bonding jumper used or EGC would normally have to be sized based on the largest breaker supplying cables and cords in the tray.

Otherwise having cable trays in non continuous sections without bonding would be a bad idea right?

I saw a post once about a non bonded/ grounded cable tray catching a roof on fire due to a line to tray short with leaves