DC power leaving a junction box

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69gp

Senior Member
Location
MA
Hi,

just wonder if this is a code violation. It is DC power for a rooftop solar system. The positive and negatives wires each exit the steel junction box through separate hole. I know with MI cable which is AC you need to slot between the conductors but I am unsure about this. This was on a project that I was at about a month ago and a few other people I know were unsure themselves about it.
thanks
Steve b
 

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69gp said:
Hi,

just wonder if this is a code violation. It is DC power for a rooftop solar system. The positive and negatives wires each exit the steel junction box through separate hole. I know with MI cable which is AC you need to slot between the conductors but I am unsure about this. This was on a project that I was at about a month ago and a few other people I know were unsure themselves about it.
thanks
Steve b
Click to expand...
The slot is needed with AC so that you do not form a single turn inductor with a ferrous core which will generate heat via hysteresis losses. That cannot happen with DC since the magnetic field is not constantly changing. If the DC were pulsed current rather than continuous, you would have heating effect similar in nature to what you have with AC.
 
GoldDigger said:
Close, but the shape and mounting methods do not match. The Cabofil web page looks like it is all stainless steel and the OP's photo looks more like vinyl covered. Without knowing a manufacturer, I would be nervous about its listing, suitabiilty for outdoor use, etc.
Click to expand...

Cablofil is available in galvanized, stainless, and painted. We are using it for LV applications a lot.
 
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