480v. and 120v. in same conduit
- Thread starter ShawnP.
- Start date
- Status
- Location
- Massachusetts
Re: 480v. and 120v. in same conduit
Yes
Yes
- Location
- Windsor, CO NEC: 2017
- Occupation
- Service Manager
Re: 480v. and 120v. in same conduit
See 300.3(C)(1).
See 300.3(C)(1).
- Location
- New Jersey
- Occupation
- Journeyman Electrician
Re: 480v. and 120v. in same conduit
I would add that if your jurisdiction is using the 2002 NEC and your installation had neutrals for both systems than you would need to identify one of the neutrals with a white color and continuous stripe. See 200.6(D) in the 2002 NEC.
I would add that if your jurisdiction is using the 2002 NEC and your installation had neutrals for both systems than you would need to identify one of the neutrals with a white color and continuous stripe. See 200.6(D) in the 2002 NEC.
johndeereman
Member
Re: 480v. and 120v. in same conduit
Also keep inmind Art.210.4(D) - Where accessible(eg.pull boxes/J-boxes) you need to identifythe ungrounded conductors by phase & system.
Also keep inmind Art.210.4(D) - Where accessible(eg.pull boxes/J-boxes) you need to identifythe ungrounded conductors by phase & system.
- Location
- Massachusetts
Re: 480v. and 120v. in same conduit
There is no 210.4(D) in the 2005 NEC.
Now for 2005 we have 210.5(C) which requires all ungrounded conductors in a building with more than one voltage system where accessible to be identified only by system not by phase and system as it had been in 210.4(D)
In other words all 3 phases of 208 can be black and all 3 phases of 480 could be blue.
John that only applied to conductors of a multiwire branch circuit.
There is no 210.4(D) in the 2005 NEC.
Now for 2005 we have 210.5(C) which requires all ungrounded conductors in a building with more than one voltage system where accessible to be identified only by system not by phase and system as it had been in 210.4(D)
In other words all 3 phases of 208 can be black and all 3 phases of 480 could be blue.
Re: 480v. and 120v. in same conduit
Standard color code in Ohio for 277Y480 volts is brown, orange, yellow, and slate a.k.a. gray. In fact, some inspectors will not allow those colors on 120Y208 volts even if there is no 480 volts in the building.
However, I would NOT install 480 ungrounded in the same pipe as 120 volts. 480 volts ungrounded systems have been shown to have an AC overvoltage of up to 2,000 volts from capacitance effects.
I have installed both 120 volts 2-wire and 480 volts 3-wire off of a 277Y480 volts system with 200 amp class J fuses in the feeder. Actually, class J fuses were mandantory so that the busway plug would meet 1987 NEC wire bending space increase.
A forklift truck did shear off 1 such feed that had #12 for the 120 volts and #6 for the 480 volts. Tripped both breakers and blew the class J feeder fuses. I can tell you that putting 12 volts and 277Y480 in the same conduit has been TESTED as safe!
Standard color code in Ohio for 277Y480 volts is brown, orange, yellow, and slate a.k.a. gray. In fact, some inspectors will not allow those colors on 120Y208 volts even if there is no 480 volts in the building.
However, I would NOT install 480 ungrounded in the same pipe as 120 volts. 480 volts ungrounded systems have been shown to have an AC overvoltage of up to 2,000 volts from capacitance effects.
I have installed both 120 volts 2-wire and 480 volts 3-wire off of a 277Y480 volts system with 200 amp class J fuses in the feeder. Actually, class J fuses were mandantory so that the busway plug would meet 1987 NEC wire bending space increase.
A forklift truck did shear off 1 such feed that had #12 for the 120 volts and #6 for the 480 volts. Tripped both breakers and blew the class J feeder fuses. I can tell you that putting 12 volts and 277Y480 in the same conduit has been TESTED as safe!
- Location
- Massachusetts
Re: 480v. and 120v. in same conduit
Is there a local ordnance that they can cite or do they just make up rules as they inspect?
johndeereman
Member
Re: 480v. and 120v. in same conduit
In responce to "iwire". is this not going to be a multiwire branch circuits if you have two diffrent voltages???? Also the industry norm is the way "mc5w" stated that 277/480 is Brown, Orange,Yellow, Gray for the grounded conductor & 120/208 is Black,Red,Blue & White for the grounded conductor & no it is not writen any where how ever this is a good safe practice.
In responce to "iwire". is this not going to be a multiwire branch circuits if you have two diffrent voltages???? Also the industry norm is the way "mc5w" stated that 277/480 is Brown, Orange,Yellow, Gray for the grounded conductor & 120/208 is Black,Red,Blue & White for the grounded conductor & no it is not writen any where how ever this is a good safe practice.
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