Nietz001
Member
- Location
- St Paul MN
I have a 120 volt ac roof top unit with 24 dc controls. Can I install them in the same raceway as long as both of them have insulation rated for 600 volts? We have several opionions within our group.
Mixing voltages
- Thread starter Nietz001
- Start date
- Status
Can you? Yes. Should you? No. (IMO)
- Location
- Illinois
- Occupation
- retired electrician
Most AC units have a Class 2 power supply for the controls. If so see 725.136.
IamJonscranium
Member
- Location
- Ohio
^ If this doesn't apply, then my answer would be that it isn't about mixing voltages amplitude since your insulation is the equal, it's about mixing AC power with DC power.
Standard practice is no. I've never done it.
ETA: It might be obvious to others, but I've never done A/C circuits. We're talking 24VDC digital signals?
- Location
- New Jersey
- Occupation
- Journeyman Electrician
Agreed. Class 2 conductors cannot be in the same raceway as power conductors even if their insulation voltage ratings are equal.
- Location
- Illinois
- Occupation
- retired electrician
There is no code rule that says you can't mix AC and DC. All of the A/C controls I have worked with were AC.
Twoskinsoneman
Senior Member
- Location
- West Virginia, USA NEC: 2020
- Occupation
- Facility Senior Electrician
Yeah the foundation of the rule is that you MAY mix AC and DC.
300.3(C) Conductors of Different Systems.
(1) 600 Volts, Nominal, or Less. Conductors of ac and dc
circuits, rated 600 volts, nominal, or less, 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.
- Status