Is it uncool to run alarm wire next to HV
- Thread starter Bzncrewjr
- Start date
I am not an electrician but I have read that it is against code to terminate low voltage and high voltage wires in the same enclosure unless they are properly spaced from each other. I think that they must be 1/4" from each other? I don't know if it is acceptable to bundle insulated LV and HV wires but not knowing any better I have done it with no problems here.
I have a house built in the 60's and the builder ran HV AC Romex wires along the face of the ceiling joists from one end of the basement to the other. I ran a cat6 cable together with this bundle to carry the rs-485 data bus from my Elk panel to the other end of the house and another that is part of my IP LAN and it works fine. From a technical point of view the danger is that you induct noise from the AC lines into the data bus and that hasn't been a problem for me. From a safety point of view the danger is having the AC line cross with the small gauge wire causing a fire or electrical shock. Being that the wires are all well insulated I am not concerned with this happening either.
To sum it up I would prefer to run the security wires seperate from high voltage wires but life is full of compromise. It was just convenient for me to use the same path. I will be interested to hear from others how they feel about this.
Mike.
EDIT:
I'd bet that NEC code dictates if it is allowed or not and maybe someone else here can answer that question.
I have a house built in the 60's and the builder ran HV AC Romex wires along the face of the ceiling joists from one end of the basement to the other. I ran a cat6 cable together with this bundle to carry the rs-485 data bus from my Elk panel to the other end of the house and another that is part of my IP LAN and it works fine. From a technical point of view the danger is that you induct noise from the AC lines into the data bus and that hasn't been a problem for me. From a safety point of view the danger is having the AC line cross with the small gauge wire causing a fire or electrical shock. Being that the wires are all well insulated I am not concerned with this happening either.
To sum it up I would prefer to run the security wires seperate from high voltage wires but life is full of compromise. It was just convenient for me to use the same path. I will be interested to hear from others how they feel about this.
Mike.
EDIT:
I'd bet that NEC code dictates if it is allowed or not and maybe someone else here can answer that question.
I can't speak from the code position, but generally you never want to run LV wires parallel to HV wires in close contact for very far. Try to run them perpendicular to each other. Short distances are probably fine, but the longer the two in close proximity to each other are parallel to each other, the more likely the LV wires will pick up noise. If they are parallel I would try to separate them by a foot if you can. Perpendicular is typically not a problem.
There really isn't an issue with running LV parallel with HV lines >240V. If it were, then EVERY piece of trough, ladder, or cable tray out there on larger installs or integrations and commercial projects, let alone residential would be in violation or there would be a lot more issues with induced and interference. The only item for HV/LV is maintaining separation of voltages or "like" rated insulations on cable (LV using THHN can occupy the same conduit as HV and not be a violation, but that's an academic exercise).
The real item to consider is what the induction actually is and what is being put on the LV cable and what's it being used for.
Audio, you want to separate or cross at 90's. The other LV, it's really inconsequential on 99% of the installs out there.
The real item to consider is what the induction actually is and what is being put on the LV cable and what's it being used for.
Audio, you want to separate or cross at 90's. The other LV, it's really inconsequential on 99% of the installs out there.
For sensors, it's a low impedance circuit, and filtered. I would expect it takes massive amounts of current to be induced to trigger the alarm circuit. A few millivolts here and there won't trip it.
The keypad lines are RS485, which is differential, so any noise get induced on both wires, and cancel each other out.
Line level (non-differential) audio is high impedance, and you could easily notice noise spikes.
The keypad lines are RS485, which is differential, so any noise get induced on both wires, and cancel each other out.
Line level (non-differential) audio is high impedance, and you could easily notice noise spikes.
