brassy
join:2004-01-09
Brantford, ON
 ·TekSavvy Solutions..
| Fairly powerful shock from touching green line Is this normal?
I was rewiring, and the green line was giving quite an awful shock. It forced me to drop it and jump back a little.
I have done some phone work before, and never experienced anything like this.
What would it be a sign of? if anything? | |
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sbrook
Premium,Mod
join:2001-12-14
H0H 0H0 | Re: Fairly powerful shock from touching green line No, it's not normal. What else were you touching?
Normally you'll only get a significant shock if ringing is being applied to your line. | |
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Keith
Why Ask Than?
Premium
join:2002-10-28
Fort Erie, ON
| said by brassy  :What would it be a sign of? if anything? 2 things come to mind
1) ring ring
2)it's a sign you should not work on your phone line:) | |
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DKS
Damn Kidney Stones
Premium,ExMod 2002
join:2001-03-22
Owen Sound, ON
clubs: | The phone was ringing. The green wire is the ring. Red is tip. Ring voltage is between 70 and 90 volts DC.
Either that or your brain rebooted... | |
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brassy
join:2004-01-09
Brantford, ON
·TekSavvy Solutions..
1 edit | Re: Fairly powerful shock from touching green line Theres just no way the phone was ringing though. I had a cordless one (connected to another jack) and it didnt ring.
I think im just going to stay away from that line. 
The only thing I would be touching would be the plastic phone jack. | |
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DKS
Damn Kidney Stones
Premium,ExMod 2002
join:2001-03-22
Owen Sound, ON
clubs: | Re: Fairly powerful shock from touching green line Or you have a bad Bell ground. | |
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chrispi5
join:2004-07-11
Toronto, ON
| said by brassy :Theres just no way the phone was ringing though. I had a cordless one (connected to another jack) and it didnt ring. You did not hear it cause you rang instead. | |
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me13
@bell.ca
| Re: Fairly powerful shock from touching green line The phone line has 48 volts on it when on hook, but if you touch one side and either you are a good path to ground or another part of your body is touching another wire, metal structure, waterpipe, etc you will get a small usually harmless jolt. I think most of the jolt is from the unexpectiveness of receiving the jolt. | |
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sbrook
Premium,Mod
join:2001-12-14
H0H 0H0
 ·Rogers Hi-Speed
Host:
Rogers
Bell Canada
1 edit | said by DKS :Ring voltage is between 70 and 90 volts DC. I hope not or the clapper in an old bell would hit one of the gongs and stay there! Ring in N. Am. phones is nominally 88V AC 20Hz superimposed on the 48V supervisory standing voltage between Red and Green. (For the UK, that's 60-75V AC 25Hz)
OP ...
You can't have gotten a shock from touching the green wire alone. You had to be touching something else, AND you had to have fairly moist fingers to get a significant belt from the supervisory voltage only. Having worked on old strowger exchanges, the 48V supervisory voltage is enough to "bite" when shocked with dry hands, but not to kick. It takes ringing to do that! | |
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DKS
Damn Kidney Stones
Premium,ExMod 2002
join:2001-03-22
Owen Sound, ON
clubs: | Re: Fairly powerful shock from touching green line You did the same search I did.  | |
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sbrook
Premium,Mod
join:2001-12-14
H0H 0H0 | Re: Fairly powerful shock from touching green line Yeah, except that the guy who wrote the original got it wrong too ... he had the frequency at 25Hz, which for MOST old bell phones was too fast for the clapper! | |
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rizzler
join:2004-07-07
canada | Re: Fairly powerful shock from touching green line your line isn't probably grounded. | |
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me13
@bell.ca | Re: Fairly powerful shock from touching green line Most of the time the inside wire is not grounded. | |
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BTS Niagara
join:2006-06-22
St Catharines, ON
| said by DKS :The phone was ringing. The green wire is the ring. Red is tip. Ring voltage is between 70 and 90 volts DC. Either that or your brain rebooted... RED is the ring on inside wire(quad)green is tip and normally the ground side but the polarity obviously got reversed somewhere. and he must have been grounded causing the shock(shock happens)no big deal, no reason to get scared of playing with phone wires | |
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sbrook
Premium,Mod
join:2001-12-14
H0H 0H0 | Re: Fairly powerful shock from touching green line There is no ground side ... red and green are both offset to ground under normal circumstances. Otherwise party lines and other requirements for ground offset signalling such as "message" would never have worked. | |
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BTS Niagara
join:2006-06-22
St Catharines, ON | Re: Fairly powerful shock from touching green line if you put an ohms meter on the ground side it will show a ground
ring shows voltage | |
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reelq
@rogers.com | Re: Fairly powerful shock from touching green line Sometimes... | |
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| | | | LazMan
join:2003-03-26
Angus, ON
·TekSavvy Solutions..
| If either side of the pair is dead-shorted to ground, you'll get a BAD hum on the line...
As has been said, nominal voltage in North America is -48vdc. Ring current, on a standard 1FL is between 60-110vAC at 20Hz.
As for 'ground' on the one side - you'll be seeing 0v differential to ground; that's not the same thing as being grounded...
Anyways - it's possible, espically in this humid weather, to get a shock from the voltage on the line - although it's more of an annoyance then painful. The sweating we're all doing right now increases the skins conductance, and allows the lower voltage/current to pass thru the body. Ring current, is painful!
Laz | |
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sbrook
Premium,Mod
join:2001-12-14
H0H 0H0
·Rogers Hi-Speed
Host:
Rogers
Bell Canada
| Re: Fairly powerful shock from touching green line You want the belts you get from old strowger equipment ... even though you're only switching 48V to get the ring, because of all the inductors on the line, you get very high spikes on every ring pulse. We checked it with an scope and found up to 400V spikes on every cycle, measured by a true RMS meter, the result was closer to 55V ... but that kicked! | |
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| | | | | | LazMan
join:2003-03-26
Angus, ON
·TekSavvy Solutions..
| Re: Fairly powerful shock from touching green line One tester I used to work with, thought it was funny as HELL to start making 'test calls' on cables we weren't finished with. Nothing like banging your hands off the back of wire-wrap blocks as ring-current runs through you... But he got his... One day, managed to get him out into the field on a 'complex issue' - while he had a hand-full of pair, buddy at the next cross-box fired up the megger...
The tester realized that maybe he wasn't so funny after all.
Laz | |
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sbrook
Premium,Mod
join:2001-12-14
H0H 0H0 | Re: Fairly powerful shock from touching green line Yeah, hitting him with a megger is NOT a nice idea! | |
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| | | | | | | | LazMan
join:2003-03-26
Angus, ON
·TekSavvy Solutions..
| Re: Fairly powerful shock from touching green line said by sbrook :Yeah, hitting him with a megger is NOT a nice idea! You're right - but he didn't seem to understand why we didn't see the humour in the test-call thing, until after the megger thing.... | |
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joshb
Don't sweat the small stuff.
Premium
join:2006-03-04
Calgary, AB
clubs: | How much extra voltage does a DSL connection add too the line? | |
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sbrook
Premium,Mod
join:2001-12-14
H0H 0H0
·Rogers Hi-Speed
Host:
Rogers
Bell Canada
| Re: Fairly powerful shock from touching green line Nothing worth noting. The reason for a 48V connection for conventional telephones is now largely historical ... The network could be run on significantly lower voltages were it not for all the equipment designed for 48V supervisory currents and 60V+ ringing current.
Amongst other reasons, carbon microphones needed a significant bias current to work properly and with their inherent resistance, voltages over about 40V were required for reliability. Ringers needed 60V plus to make the bells work. The relays and selectors (uniselectors, and 2 motion selectors) in early strowger exchanges worked best with about 48V operating voltages to combine reliability and speed etc. Also, party line selection which was done by grounding a circuit may result in higher resistance completing the circuit.
DSL doesn' add much at all by comparison. | |
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