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Posted By: SJT Mix of Conductors - 02/05/11 04:26 AM
In the same conduit are you allowed to run normal 60hz and also 50hz conductors? as long as they are marked? There is a conduit that was run for equipment that has controls of 50hz. We want to pull #10's through the same conduit for a small water heater, which will be 60hz.
Thanks - SJT
Posted By: gfretwell Re: Mix of Conductors - 02/05/11 08:42 AM
I don't think the NEC even talks about line frequency. As long as they are all chapter 3 wiring methods below 600v I think they can live together.
Posted By: SJT Re: Mix of Conductors - 02/05/11 02:56 PM
Thanks Greg, Going through the existing conduit would save alot of Labor and material.
Posted By: gfretwell Re: Mix of Conductors - 02/05/11 06:34 PM
Derating might be an issue
Posted By: LarryC Re: Mix of Conductors - 02/05/11 06:37 PM
Not a code issue but a operational check.

When the water heater elements switch on and off, will the induced voltages interfere with the 50 Hz controls?

Larry C
Posted By: SJT Re: Mix of Conductors - 02/06/11 04:27 AM
Good Point,
I'm not sure how the two HZ's would react. I'd rather not go that route if there is a possible problem. Could a wire with a different HZ induce something onto the other conductors? I guess that is the question.
SJT
Posted By: gfretwell Re: Mix of Conductors - 02/06/11 07:12 AM
I don't see a problem. If you think so, twist the wires a few times.
Posted By: LarryC Re: Mix of Conductors - 02/06/11 12:36 PM
I am not as concerned about the difference in frequency, it is more of a concern about how sensitive the 50 Hz CONTROL lines are.

The controls are are relays and lamps, no big deal. If the controls lines are for frequency meters or high impeadance sensors, then yes, it could be a big deal.

Are the control wires shielded? Do you know what type of signals are on these wires?
Posted By: harold endean Re: Mix of Conductors - 02/07/11 02:42 PM
My old boss use to work in a big factory here in northern NJ and they use to have many different frequency lines. ( I believe they did a lot of work for satellites)What they would do is make sure that the odd frequency wires were marked and labeled with different colors. (Like purple) This way they didn't get the 120/240 red, blue, black and the 277/480 Brown, orange, yellow mixed up with the 500 Hz which was purple.
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