AC & DC in same conduit

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iwire said:
I can run a 20 amp branch circuit in a conduit with a 1200 amp feeder.
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Yes you can,whats your point ?They both are protected.Your missing something Bob.The source of power is now from the battery not your AC INPUT.Its not fused at all.

Actually i wanted to do just that for a block heater on a gen. but my boss did not like the idea.And it would have forced my derateing off 500 mcm because of a stupid 20 amp circuit
 
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I think Jim's point is that the battery at the outlet is a source of power, unlike the toaster at the end of the 20A branch circuit running next to the feeder.

Jim, wouldn't the branch circuit OCPD protect as well in a backfeed for the conductors in question?

If anything, a connection from the battery to the AC source would probably damage the battery before the conductors, I would think. But I don't know.
 
georgestolz said:
I think Jim's point is that the battery at the outlet is a source of power, unlike the toaster at the end of the 20A branch circuit running next to the feeder.

Jim, wouldn't the branch circuit OCPD protect as well in a backfeed for the conductors in question?

If anything, a connection from the battery to the AC source would probably damage the battery before the conductors, I would think. But I don't know.
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Likely yes,but what if the cable shorted out.Then it is unfused.Fuses are not needed ever for proberly wired and loaded circuits.A house could do fine for 20 years with no fuses or breakers.
 
Jim W in Tampa said:
Yes you can,whats your point ?They both are protected.Your missing something Bob.The source of power is now from the battery not your AC INPUT.Its not fused at all.
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First unless one side of the battery is bonded to ground a single connection between the battery and the AC would do nothing.

Next regardless of which way the power is going to or from if my 20 amp branch circuit faults to my 1200 feeder protected or not the 12 AWG will be history.
 
iwire said:
Jim, What exactly do you see happening?
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Not sure what he sees, but I see the charging cable melting a nice hole in your 1200A feeders and doing who knows what damage.

It doesn't cost all that much to put a 20A fuse inline with the charging cable. Unless the charger is providing more than 20A charging current (that's a pretty phat battery if it does), the fuse would only blow if a short occurs between the charging cables on the other side of the fuse.
 
tallgirl said:
Not sure what he sees, but I see the charging cable melting a nice hole in your 1200A feeders and doing who knows what damage.

It doesn't cost all that much to put a 20A fuse inline with the charging cable. Unless the charger is providing more than 20A charging current (that's a pretty phat battery if it does), the fuse would only blow if a short occurs between the charging cables on the other side of the fuse.
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Exactly what i see.Bob ,if the battery side melts it makes no differance if its neg or pos is grounded.Its a small fire within the conduit.
 
Back ot the OP,I would say it is legal as long as both conductors ins. is rated for the highest voltage present.
IMO,it would be poor practice from my experience with AC/DC and the threads posted
 
i would'nt do it your asking for trouble.
we used to run seperate conduits for dc and lable it
(factory standards) and just good common sense...

jmo
 
Here is a good explaination
Pulse-width modulation control works by switching the power supplied to the motor on and off very rapidly. The DC voltage is converted to a square-wave signal, alternating between fully on (nearly 12V) and zero, giving the motor a series of power "kicks".

If the switching frequency is high enough, the motor runs at a steady speed due to its fly-wheel momentum.

By adjusting the duty cycle of the signal (modulating the width of the pulse, hence the 'PWM') ie, the time fraction it is "on", the average power can be varied, and hence the motor speed.
 
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