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#198811 02/04/11 11:26 PM
Joined: Jul 2002
Posts: 241
S
SJT Offline OP
Member
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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SJT #198816 02/05/11 03:42 AM
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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.


Greg Fretwell
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SJT Offline OP
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Thanks Greg, Going through the existing conduit would save alot of Labor and material.

SJT #198823 02/05/11 01:34 PM
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Derating might be an issue


Greg Fretwell
SJT #198824 02/05/11 01:37 PM
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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

Joined: Jul 2002
Posts: 241
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SJT Offline OP
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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

SJT #198862 02/06/11 02:12 AM
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I don't see a problem. If you think so, twist the wires a few times.


Greg Fretwell
SJT #198865 02/06/11 07:36 AM
Joined: Jul 2004
Posts: 787
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Member
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?

SJT #198891 02/07/11 09:42 AM
Joined: Feb 2002
Posts: 2,233
H
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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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