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Subject - Multiple voltages in single jbox?
veganfan


Does anyone know if there are any rules in code about having different voltages in one j box? My coworkers have told me for years that it is illegal to run 480v and 120v in same j box or EMT. Now that studding code can not find this any where. Does it exist?
JimmyDee
quote:
Article 300.3(C) Conductors of Different Systems.
(1) 600 Volts, Nominal, or Less. Conductors of circuits rated 600 volts, nominal, or less, ac circuits, and dc circuits shall be permitted to occupy the same equipment wiring enclosure, cable, or raceway. All conductors shall have an insulation rating equal to at least the maximum circuit voltage applied to any conductor within the enclosure, cable, or raceway.

It is totaly acceptable. They have to be insulated the same and in case of a 480-120 volt deal, they would both have to be 600 volt wire anyway.
Jim
cs409 just on safe note, i think i would mark the cover to show u have 120 and 480,,,,just incase someone is in the box and well, u know,,,,
aussiesparky Came across someting similar today [Thursday] 3 single phase 240v lighting supplies in one junction box. All on different phases.
Nice 415v potential for the next guy who came along.
Needless to say It's not there now, 1circuit 1 junction box one voltage.
SteveMc Aussiespark, Is that not allowed in Australia or just a personal preference? We commonly run three 277v lighting circuits in the same conduit. As a personal preference of my own, I won't run two different volages in the same conduit and always color code my wiring 480/277 b,o,y and 208/120 bk,rd, bl.
cs409 good common sense makes good electricians....its good to see some that care and take the time to leave a little note! i use a marker pen to indicate if there is a 4way switch in the system! i remember once that a 4 way was in lighting system on a back porch(screened)where the 4way switch was located in the ladies bedroom!
veganfan So it is that its is not agianst code, but as we all agree it is not logical or safe. correct?
aussiesparky Steve
Should have clarified the supply cables to the lights were TPS [Rommex] and all (3) junctioned in 1 Jbox.
We also run multiple 240v circuits in conduit as well.
I think we all agree with Casey and Dan.
Safe, logical and think of the next guy who will work on it after you.
JimmyDee
quote:
Originally posted by veganfan

So it is that its is not against code, but as we all agree it is not logical or safe. correct?

I see nothing unsafe or illogical about this. It is nice to maybe write on or in a j box what the wires are but that is not necessary either.
Jim
Ryan_J Watch out for

404.8(B) Voltage Between Adjacent Devices. A snap switch shall not be grouped or ganged in enclosures with other snap switches, receptacles, or similar devices, unless they are arranged so that the voltage between adjacent devices does not exceed 300 volts, or unless they are installed in enclosures equipped with permanently installed barriers between adjacent devices.

New change to the 2002 says "devices". 99 said "switches", and therefore this section has expanded in its requirements. J-box with no devices is fine though. :)
veganfan
I think the people at my work are confused with the fact that class 2 low voltages and line voltages.

They tend to get a lot of them con
fused such as they told me for along time that liquitite can not exceed 6 feet in length.
Chris Clement When you describe 480 volts, do you mean phase-to-phase? Any conductor should be no more than 277 volts from ground? Am I correct or mistaken?
JimmyDee Yes, phase to phase. We typical don't see voltages higher than 277 from phase to ground in typical building power but in industry you will see power to large motors etc that will be 7200 volts to ground (12,470 volts will be phase to phase on this system) and that is a typical voltage the power companies will use also.
Jim