electric shock

[foghorn]

is it possible to get an electric shock from a phone point and if so what could cause this

 

[Stuuk1]

I'd be very interested to know the ringing voltage.

My line of work is in telecoms. I have installed the DC power plants for years.
I know that everything in the exchanges is -54.5v DC with equipment obviously running on battery backup of -48v DC.

Therefore a ringing voltage can't be more than 96v DC can it? If you had + and - voltages...

Certainly not A/C anyway.

 

[Des 56]

is it possible to get an electric shock from a phone point and if so what could cause this

Now that all the genuine answers have been given,its time to look at the question as its written and as others have said,watch out for that lightning strike

quote

MythBusters Jamie Hyneman and Adam Savage confirmed this common safety advice, based on the possibility that lightning could strike whatever building you're inside. If that happens, the powerful bolt of electricity will look for the quickest route to the ground via wiring. An electrified phone line could then send dangerous vibrations up to the phone's mouthpiece and deliver an earful of lethal shock.
The MythBusters zapped a makeshift house with 300,000 volts of electricity to chart lightning's potential path from the ground wiring to the phone held by ballistics gel dummy Buster. The gel inside Buster shares the same electrical resistance as human flesh, and a heart monitor hooked to him measured how big of a zap his body received from the hot phone.

When they released the electricity, it quickly hopped from the phone wiring to Buster's heart, blowing out the monitor device. Since the machine maxed out at 40 milliamps, the amount of electricity pulsing through the conduit must've far exceeded the lethal 6-milliamp mark.
Unfortunately, this myth also has been confirmed the hard way: About two people die from lightning strikes through phone lines each year

 

[DPG]

50VDC steady state. Higher voltage AC when ringing. Always used to be anyway, just Google it to see if it still is. I would think so, since old phones still work on the network. My exchange still lets me use my BT rotary dial phone, and that's pulse dialing, none of your fancy DTMF! Daz

 

[sedgy34]

I wreckon he means the tv point

 

[telectrix]

having just done a google search, i stand corrected. the ring voltage was 90V @ 20Hz. apparently this has been reduced for the modern phones to around 60V

 

[DPG]

Must admit I didn't know they'd dropped it. ALways used to be around 90VAC. Definately enough for a tingle. And enough to show a spark in a dark room when there was a poor connection! Definately more than the 50VDC network supply anyway. Daz

 

[Marvo]

The main jack point in a house should have a gas discharge lightning protector in it but I still wouldn't want to be on the phone during a direct lightning strike.

 

[HandySparks]

I'd be very interested to know the ringing voltage.

My line of work is in telecoms. I have installed the DC power plants for years.
I know that everything in the exchanges is -54.5v DC with equipment obviously running on battery backup of -48v DC.

Therefore a ringing voltage can't be more than 96v DC can it? If you had + and - voltages...

Certainly not A/C anyway.

Yes. Somewhere in the exchange will be a ring voltage generator. Originally electro-mechanical, now electronic. The AC ring voltage is imposed on top of the -48V DC on the line.

I'm not a telecoms expert; you'll have to look up the details yourself.

However it's generated, it's not limited to the -48V supply voltage.

 

[Geordie Spark]

mainly when it rings. that's 120V A.C. gives a jolt but not sufficient current to be fatal.

I agree

 

[Stuuk1]

Next time I'm in an exchange I shall find out and report back!