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GabeS
01-26-2009, 07:20 AM
Do you need an electrical license to work with low voltage wiring? ex.) telephone, cable, computer, alarm system, speaker system, etc.

I heard no from a union electrician. Is that true?

Also, do you typically need to get permits to run these lines in a preexisting house?

Igor
01-26-2009, 07:39 AM
It depends on where you are. Many states do require licensing for low-voltage work; some don't.

GabeS
01-26-2009, 07:46 AM
I'm in nyc.

frenchie
01-26-2009, 03:19 PM
Technically? Yes. Ever since 2001 when we adopted the NEC. But it doesn't have to be a regular electrician, there's a separate license for low-voltage wiring.

But I think it only applies to people doing it for hire; you might be okay DIYing for yourself, I'm not sure. Call the DoB and ask.

Thatguy
01-27-2009, 02:49 PM
I think there is zero likelihood of dying with less than 47v and less than 18 mA. The NEC seems to relax with less than 30vrms, less than 42v peak and less than 60 vdc.

The phone line delivers about 56vdc at a max. current of ~170mAdc, but the ringing signal is a bit more than 90vrms.
I doubt it ever killed anyone.

jadnashua
01-27-2009, 04:45 PM
Well, if you weren't expecting it, the ring voltage might make you fall off a ladder:D. I know it creates a big surprise if you're holding it when it happens.

Thatguy
01-28-2009, 07:29 AM
Well, if you weren't expecting it, the ring voltage might make you fall off a ladder:D. I know it creates a big surprise if you're holding it when it happens.
Turns out falling or jumping off a 2' ladder dumps as much energy into your body as several bullets. With knees locked, the power dumped into you is very high because the deceleration is very high.
The Darwin Awards are always lookin' for people!