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#198811 - 02/04/11 08:26 PM Mix of Conductors
SJT Offline
Member
Registered: 07/24/02
Posts: 241
Loc: PATCHOGUE, N.Y.
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
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#198816 - 02/05/11 12:42 AM Re: Mix of Conductors [Re: SJT]
gfretwell Offline


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Registered: 07/20/04
Posts: 9039
Loc: Estero,Fl,usa
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.
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Greg Fretwell
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#198819 - 02/05/11 06:56 AM Re: Mix of Conductors [Re: gfretwell]
SJT Offline
Member
Registered: 07/24/02
Posts: 241
Loc: PATCHOGUE, N.Y.
Thanks Greg, Going through the existing conduit would save alot of Labor and material.
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#198823 - 02/05/11 10:34 AM Re: Mix of Conductors [Re: SJT]
gfretwell Offline


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Registered: 07/20/04
Posts: 9039
Loc: Estero,Fl,usa
Derating might be an issue
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Greg Fretwell
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#198824 - 02/05/11 10:37 AM Re: Mix of Conductors [Re: SJT]
LarryC Offline
Member
Registered: 07/05/04
Posts: 780
Loc: Winchester, NH, US
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
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#198853 - 02/05/11 08:27 PM Re: Mix of Conductors [Re: LarryC]
SJT Offline
Member
Registered: 07/24/02
Posts: 241
Loc: PATCHOGUE, N.Y.
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
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#198862 - 02/05/11 11:12 PM Re: Mix of Conductors [Re: SJT]
gfretwell Offline


Member
Registered: 07/20/04
Posts: 9039
Loc: Estero,Fl,usa
I don't see a problem. If you think so, twist the wires a few times.
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Greg Fretwell
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#198865 - 02/06/11 04:36 AM Re: Mix of Conductors [Re: SJT]
LarryC Offline
Member
Registered: 07/05/04
Posts: 780
Loc: Winchester, NH, US
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?
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#198891 - 02/07/11 06:42 AM Re: Mix of Conductors [Re: SJT]
harold endean Offline
Member
Registered: 02/16/02
Posts: 2233
Loc: Boonton, NJ
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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