Power Out - Day Two

[Steve_Miller]

I was told the transformers work both ways, power back feed into the lines can be stepped up to thousands of volts and could potentially kill a person working the lines. I cannot verify, maybe someone who works for a utility could provide some input.

Yes, a transformer does work that way and yes you can kill someone of they do not protect themselves from the hazards while working on lines. I'm not a lineman, but anytime I've seen or talked to lineman working on downed lines they have grounding lines they connect from phase to phase and to ground at the last disconnection point to protect them from some other person from re-energizing the lines while they may working down the line several miles. It's their protection from someone doing something their not suppose to do whether it be reconnecting the inline switches or the distribution center re-energizing a feed on which they are working. Anytime they are working on live lines, they are to be in contact with a central dispatch. Up here in Nova Scotia (NSPI) lineman sometimes work alone, when they do they have to contact or be contacted I think every twenty minutes and if no contact is made someone is sent immediately to their location to investigate why they did not call or reply. Sorry if I'm stealing someones thread.

Steve

 

[IXLR8]

I was told the transformers work both ways, power back feed into the lines can be stepped up to thousands of volts and could potentially kill a person working the lines. I cannot verify, maybe someone who works for a utility could provide some input.

You are correct!! Transformers don't care which way you are feeding power to them. If you have a step down transformer taking 10,000 volt line down to 220 volt for you to use in your home. Then when you backfeed 220 volt from your generator to the transformer.. it puts out 10,000 volts to the line!!!!!!!! This would certainly ruin a line workers day!! This is why it is a legal requirement to have a transfer switch to isolate your generator from the incoming line. Line workers are suppose to check the line to make sure it is dead before touching it. But if they don't, or you fire up the generator after they have checked it, and they get killed, a generator operator with no transfer switch will have LOTS of explaining to do!!

 

[Travelover]

Don't forget that when you back feed a line it is still connected up to hundreds of customer's houses which all want lots of power NOW.

I use a transfer switch on my set up, but I think the danger of killing a line man may be overstated. Anyone heard of it actually happening?

 

[LBrown59]

You are correct!! Transformers don't care which way you are feeding power to them. If you have a step down transformer taking 10,000 volt line down to 220 volt for you to use in your home. Then when you backfeed 220 volt from your generator to the transformer.. it puts out 10,000 volts to the line!!!!!!!!

I have an elect train transformer.
If you hook 12 volts to the 12 volt terminals you will get 110 on the cord that plugs into a wall out let.

 

[jake98]

Don't forget that when you back feed a line it is still connected up to hundreds of customer's houses which all want lots of power NOW.

I use a transfer switch on my set up, but I think the danger of killing a line man may be overstated. Anyone heard of it actually happening?

There are all different situations and they can be changing also. I don't see how you could overstate that it's wrong to risk giving a lineman a shock. If I saw somebody doing something that risky to someone else, I'd probably overreact.

 

[coobie]

Yes, a transformer does work that way and yes you can kill someone of they do not protect themselves from the hazards while working on lines. I'm not a lineman, but anytime I've seen or talked to lineman working on downed lines they have grounding lines they connect from phase to phase and to ground at the last disconnection point to protect them from some other person from re-energizing the lines while they may working down the line several miles. It's their protection from someone doing something their not suppose to do whether it be reconnecting the inline switches or the distribution center re-energizing a feed on which they are working. Anytime they are working on live lines, they are to be in contact with a central dispatch. Up here in Nova Scotia (NSPI) lineman sometimes work alone, when they do they have to contact or be contacted I think every twenty minutes and if no contact is made someone is sent immediately to their location to investigate why they did not call or reply. Sorry if I'm stealing someones thread.

Steve

Good information here!! Last year when we were working a storm on a primary line 4800 volts in a rural area of S.Michigan we had a local farmer back feeding the primary line almost a mile away with his tractor driven PTO generator.When we checked the line for voltage it read 3400 volts.Thank god we did.coobie

 

[Travelover]

There are all different situations and they can be changing also. I don't see how you could overstate that it's wrong to risk giving a lineman a shock. If I saw somebody doing something that risky to someone else, I'd probably overreact.

Don't misunderstand me, I think it is vital to protect the safety of power line workers. I think the chances of getting your genset fried when the power comes on is the more likely outcome of backfeeding.

 

[LBrown59]

Don't forget that when you back feed a line it is still connected up to hundreds of customer's houses which all want lots of power NOW.

Could somebody in one of those houses get a jolt>>>>>>??

 

[Diamondpilot]

Don't misunderstand me, I think it is vital to protect the safety of power line workers. I think the chances of getting your genset fried when the power comes on is the more likely outcome of backfeeding.

That happened to a guy I know. He simply back feeds the panel through a plug in his garage regularly used for a welder. Anyway he saw the lights come on across the street so he just flipped his main back on before disconnecting the generator and fried it. He said a replacement gen head was more than a new unit at Lowes.

Chris

 

[JoelD]

No doubt about it, a three way is best way, no way to back feed. Our power is out infrequently and I'm careful to flip main but mistakes can happen, I should get an electrician out to wire up a three way inbetween my panel and my generator.

I'm thinking I'd have to coordinate with PSNH as they'd need to kill at the street?

Joel