Could I have toasted the generator?

[Rusty Wrench]

During power outs I plug the generator (Honda 3.5kw) into a 30A wall receptacle, via suicide cord, to liven the whole main panel. We run sparse loads; I know enough to not overload it.

Yesterday, with power out and generator not running, I turned off main breaker and then plugged cord to wall. Turning to generator I insert other end in and immediately hear a bad loud hum. The plug got to the point of contact (not inserted completely) with gen and was yanked out. Literally less than a second.

What happened in that period is power came back on and the main circuit breaker, though off, was only shutting down one hot leg. So I back fed 120V of grid power into a non running generator. The gen circuit breaker was turned off.

What kind of damage could I have caused? I have a call to electrician to replace the breaker. I will test after the repair but the episode has me worried about the health of the generator. Thanks

 

[mm08822]

If the gen cb was off, the grid power should not have affected the gen. If the gen cb was closed and the gen not rotating, it would experience a condition similar to a locked rotor condition. It could have fried the windings if you weren't there to disconnect it.

Get your electrician to wire in an interlocked generator input circuit properly. Look up Power Inlet Box (PIB). Lose the suicide cord.

 

[rlitman]

...Get your electrician to wire in an interlocked generator input circuit properly. Look up Power Inlet Box (PIB). Loose the suicide cord.

An inlet is a good answer, but an interlock won't fix TWO faulty breakers.

Rusty, what brand panel do you have? Not only was your main breaker defective, but the 30A breaker servicing that receptacle may have been too.

If you had an inverter generator, the generator's own protection would have tripped out instantly. In your synchronous generator's case, it's coils are protected by the inlet breaker. Since your 30A breaker didn't yet trip, either it is a bad breaker, or the current to the generator didn't exceed the thermal curve of the breaker. If the latter, your generator should be fine, since you unplugged it fast enough.

 

[mm08822]

An inlet is a good answer, but an interlock won't fix TWO faulty breakers.

Rusty, what brand panel do you have? Not only was your main breaker defective, but the 30A breaker servicing that receptacle may have been too.

If you had an inverter generator, the generator's own protection would have tripped out instantly. In your synchronous generator's case, it's coils are protected by the inlet breaker. Since your 30A breaker didn't yet trip, either it is a bad breaker, or the current to the generator didn't exceed the thermal curve of the breaker. If the latter, your generator should be fine, since you unplugged it fast enough.

A transfer switch would minimize those symptoms.

Not sure I'm ready to believe 2 seperate breakers failed but you don't know until tested.

 

[PCustoms]

Not sure I'm ready to believe 2 seperate breakers failed but you don't know until tested.

OP needs to call an electrician ASAP and get this mess fixed.

Suicide cords, bad breakers and back feeding the grid, great way to kill someone.

 

[MBfreak]

Well, to start with your backfeed was absolutely idiotic.
Learn to respect all electric safety rules, and if you do not have the capacity for that, leave it to a competent and licesed electrician

 

[Rusty Wrench]

I hadn't considered that another breaker could be faulty.

@rlitman
The main panel is branded Challenger with a W next to it (Westinghouse or Western?), circa late 80's. The gen circuit breaker is in a GE Power Mark load center that services my basement shop. That sub panel is protected by 70A breaker in the lower left corner of main panel.

@mm08822
The main panel has the load center cb near the bottom. Adding an interlock requires that a few things need to moved around in there, I think. I see the wisdom of power inlet.
An interlock is just a poor mans solution to what a transfer switch does, right?

I do have a call into electrician. This recent outage here in NE OH is massive. Many still without power. It will be a while before I'm on the schedule, I expect.

I'm not limited by funds but now the work order is more than just replacing main cb.
Namely, add interlock and power inlet box. Test all circuit devices. Anything else?

Incidentally, this all was put in by a licensed electrician. Having a clear picture of a proper install to guide the next licensed electrician is appreciated. Thank you all for your direction.

edit- removed idiot comment

 

[mike93lx]

ps I'm not an idiot.

Knowing enough to call it a suicide cord and still use it is evidence to the contrary, to be completely frank. But at least you are now getting it fixed and no one was hurt.

That type of setup can kill people and call also result in the feeder to your house getting cut when crews are out restoring service

 

[PCustoms]

Knowing enough to call it a suicide cord and still use it is evidence to the contrary, to be completely frank. But at least you are now getting it fixed and no one was hurt.

That type of setup can kill people and call also result in the feeder to your house getting cut when crews are out restoring service

He made an edit before I could capture the quote.

The "illegal" and blatantly dangerous installation is additional evidence to the contrary.

 

[mm08822]

I hadn't considered that another breaker could be faulty.

@rlitman
The main panel is branded Challenger with a W next to it (Westinghouse or Western?), circa late 80's. The gen circuit breaker is in a GE Power Mark load center that services my basement shop. That sub panel is protected by 70A breaker in the lower left corner of main panel.

@mm08822
The main panel has the load center cb near the bottom. Adding an interlock requires that a few things need to moved around in there, I think. I see the wisdom of power inlet.
An interlock is just a poor mans solution to what a transfer switch does, right?

I do have a call into electrician. This recent outage here in NE OH is massive. Many still without power. It will be a while before I'm on the schedule, I expect.

I'm not limited by funds but now the work order is more than just replacing main cb.
Namely, add interlock and power inlet box. Test all circuit devices. Anything else?

Incidentally, this all was put in by a licensed electrician. Having a clear picture of a proper install to guide the next licensed electrician is appreciated. Thank you all for your direction.

edit- removed idiot comment

I would replace the Challenger Panel with a 40+ space panel.
The interlock is used between the POCO feed and the PIB CB. Your PIB circuit in the 70A sub-panel completely screws that up.
Is there even an interlock in the sub-panel?
I think Sparkey#1 blew it (unless of course you only wanted the shop backed up).

Move the PIB CB into the new main panel directly adjacent to the main CB.

Don't call Sparkey#1 again.

 

[Metal-Marc]

During power outs I plug the generator (Honda 3.5kw) into a 30A wall receptacle, via suicide cord, to liven the whole main panel. We run sparse loads; I know enough to not overload it.

Yesterday, with power out and generator not running, I turned off main breaker and then plugged cord to wall. Turning to generator I insert other end in and immediately hear a bad loud hum. The plug got to the point of contact (not inserted completely) with gen and was yanked out. Literally less than a second.

What happened in that period is power came back on and the main circuit breaker, though off, was only shutting down one hot leg. So I back fed 120V of grid power into a non running generator. The gen circuit breaker was turned off.

What kind of damage could I have caused? I have a call to electrician to replace the breaker. I will test after the repair but the episode has me worried about the health of the generator. Thanks

Quoted for posterity.

 

[wyliesdiesels]

During power outs I plug the generator (Honda 3.5kw) into a 30A wall receptacle, via suicide cord, to liven the whole main panel. We run sparse loads; I know enough to not overload it.

Yesterday, with power out and generator not running, I turned off main breaker and then plugged cord to wall. Turning to generator I insert other end in and immediately hear a bad loud hum. The plug got to the point of contact (not inserted completely) with gen and was yanked out. Literally less than a second.

What happened in that period is power came back on and the main circuit breaker, though off, was only shutting down one hot leg. So I back fed 120V of grid power into a non running generator. The gen circuit breaker was turned off.

What kind of damage could I have caused? I have a call to electrician to replace the breaker. I will test after the repair but the episode has me worried about the health of the generator. Thanks

how do you know this is the case? did you meter the receptacle before turning the main breaker back on?

BTW this is a very good reason why you should have an interlock

 

[wyliesdiesels]

I hadn't considered that another breaker could be faulty.

@rlitman
The main panel is branded Challenger with a W next to it (Westinghouse or Western?), circa late 80's. The gen circuit breaker is in a GE Power Mark load center that services my basement shop. That sub panel is protected by 70A breaker in the lower left corner of main panel.

@mm08822
The main panel has the load center cb near the bottom. Adding an interlock requires that a few things need to moved around in there, I think. I see the wisdom of power inlet.
An interlock is just a poor mans solution to what a transfer switch does, right?

I do have a call into electrician. This recent outage here in NE OH is massive. Many still without power. It will be a while before I'm on the schedule, I expect.

I'm not limited by funds but now the work order is more than just replacing main cb.
Namely, add interlock and power inlet box. Test all circuit devices. Anything else?

Incidentally, this all was put in by a licensed electrician. Having a clear picture of a proper install to guide the next licensed electrician is appreciated. Thank you all for your direction.

edit- removed idiot comment

that electrician is a maroon.

you cant have an interlock on the 70a subpanel feeding breaker and still be able to power the basement load center with the PoCo power.

As @mm08822 stated, you will need to move this generator breaker into the main service panel.

 

[MBfreak]

And since the OP has attempted to interconnect two AC sources, there is a possibility that the two sources are 180 degrees out of phase. The utility network has a short circuit capacity that is very many times the SC capacity of the generator. The utility source will supply a very high short circuit into the generator. Guess the utility transformer is a 50 kVA unit with a short circuit impedance of 4%. BUT my knowledge of distribution network transformers in the US is VERY rudimentary.
Making a model and calculate the fault current going into the generator and the resulting overvoltage is easy if circuit parameters are known.

But the smoke test is of course a much more understandable indication.

Ola

 

[Rusty Wrench]

Thank you all for your comments. I took a little umbrage at being taken to the woodshed on my setup. But I totally acknowledge the inherent danger in the configuration as it exists. I have been reading and watching some YT to get to a better understanding of things.

Notwithstanding all the things that are wrong; I don't think I did anything wrong, per se. Gen off, gen cb off, main cb off- yet an audible fault. I don't run the gen full time during outs. Just enough to keep the food cold basically. I consider it luck the gen was not running when power returned.

An interlock would not have avoided gen feeding power to the grid or vice versa as it is the main breaker that iseems faulty. I say this because with main cb off, some circuits are live, some not. I expect it correlates to the left and right side of panel. For this reason I think a transfer switch may be an overall safer choice. If not, please correct me on any of these points.

On the point of manual vs auto transfer switch- Are they smart enough to sense voltage from both ends simultaneous? I'm guessing faulty main breaker is a pretty low probability event but it did happen to me.

On the point of a proper install, I'm still sorting out what to direct the next guy to do.
What happens at the transfer switch if current comes in at both ends?
Do I want whole panel power or should I break out dedicated circuits?
The power inlet box is a no brainer at this point.

The critics have made their points. I see it and they are well taken. The positive advice is very much appreciated and helpful towards enough learning to find a solution that is safe for my family and others. Thanks.

 

[PCustoms]

An interlock would not have avoided gen feeding power to the grid or vice versa as it is the main breaker that iseems faulty. I say this because with main cb off, some circuits are live, some not. I expect it correlates to the left and right side of panel. For this reason I think a transfer switch may be an overall safer choice. If not, please correct me on any of these points.

If this is true you have a potentially dangerous condition that needs to be resolved ASAP by a professional.

I suspect that you made an error in how you switched the generator circuits, which goes back to why the interlock should exist.

 

[mm08822]

Thank you all for your comments. I took a little umbrage at being taken to the woodshed on my setup. But I totally acknowledge the inherent danger in the configuration as it exists. I have been reading and watching some YT to get to a better understanding of things.

Notwithstanding all the things that are wrong; I don't think I did anything wrong, per se. Gen off, gen cb off, main cb off- yet an audible fault. I don't run the gen full time during outs. Just enough to keep the food cold basically. I consider it luck the gen was not running when power returned.

An interlock would not have avoided gen feeding power to the grid or vice versa as it is the main breaker that iseems faulty. I say this because with main cb off, some circuits are live, some not. I expect it correlates to the left and right side of panel. For this reason I think a transfer switch may be an overall safer choice. If not, please correct me on any of these points.

On the point of manual vs auto transfer switch- Are they smart enough to sense voltage from both ends simultaneous? I'm guessing faulty main breaker is a pretty low probability event but it did happen to me.

On the point of a proper install, I'm still sorting out what to direct the next guy to do.
What happens at the transfer switch if current comes in at both ends?
Do I want whole panel power or should I break out dedicated circuits?
The power inlet box is a no brainer at this point.

The critics have made their points. I see it and they are well taken. The positive advice is very much appreciated and helpful towards enough learning to find a solution that is safe for my family and others. Thanks.

It appears you got taken to the woodshed when it should have been Sparkey#1. At least you made it out.
Did he provide an interlock at the sub-panel?

Mechanical interference interlocks to the cb handles is the cheapest method. Yes, it relies on both cb's not failing.

A transfer switch whether auto or manual provides a physical seperation between contacts.
Manual xfer switches depend on you to actuate.
Automatic xfer switches are automated typically based on grid power presence to transfer in either direction.
There would not be a problem if both gen and grid power were on at same time - current practice in xfer switches albeit momentary.

I already gave you reccomendations for Sparkey#2. Getting rid of the Challenger panel is the easiest way to fix the main cb and get the proper interlock scheme installed, plus get more space.

 

[RalphInCA]

The critics have made their points. I see it and they are well taken. The positive advice is very much appreciated and helpful towards enough learning to find a solution that is safe for my family and others.

I am very happy that the critics spoke up in this case. Not only does it help the OP, but it helps many many others who may have possibly considered this.

All hail, the critics!

 

[wyliesdiesels]

Thank you all for your comments. I took a little umbrage at being taken to the woodshed on my setup. But I totally acknowledge the inherent danger in the configuration as it exists. I have been reading and watching some YT to get to a better understanding of things.

Notwithstanding all the things that are wrong; I don't think I did anything wrong, per se. Gen off, gen cb off, main cb off- yet an audible fault. I don't run the gen full time during outs. Just enough to keep the food cold basically. I consider it luck the gen was not running when power returned.

An interlock would not have avoided gen feeding power to the grid or vice versa as it is the main breaker that iseems faulty. I say this because with main cb off, some circuits are live, some not. I expect it correlates to the left and right side of panel. For this reason I think a transfer switch may be an overall safer choice. If not, please correct me on any of these points.

On the point of manual vs auto transfer switch- Are they smart enough to sense voltage from both ends simultaneous? I'm guessing faulty main breaker is a pretty low probability event but it did happen to me.

yes auto transfer switch has capability to read grid and generator voltage. but if you go with an AT you will either need to size the generator to handle the entire load or use load shedding modules

On the point of a proper install, I'm still sorting out what to direct the next guy to do.
What happens at the transfer switch if current comes in at both ends?
Do I want whole panel power or should I break out dedicated circuits?
The power inlet box is a no brainer at this point.

nothing because the transfer would only be connected to one source at a time.

 

[Rusty Wrench]

@mm08822
Your advice is clear, well received and figure into the upgrade. Much thanks. No, no interlock installed on sub panel either. Sub panel cb is in main panel.
Liking better the idea of transfer switch, probably manual.

Still hoping for a quick response from electrician. I expect they're still busy due to storm work. Thanks all. I will update with, well... updates.

 

[rlitman]

...nothing because the transfer would only be connected to one source at a time.

In theory, yes. I've experienced two different types of failure in UL listed transfer switches (one ended in a dead short), but in general, a transfer switch should be more reliable than a circuit breaker, and circuit breakers should be very reliable on their own, yet many of us have seen breakers that fail to open, just like the OP's issue. There's a reason we always check all three phases to ground before going hands-on with de-energized equipment.

There are various methods of interlocking transfer switches. The knife blade manual transfer switches I'm familiar with, rotate the same contacts through for both positions, so there is physically no way to connect the utility side to the emergency side (even if the blade broke, it wouldn't be long enough to span the gap). A good ATS uses a mechanical interlock that prevents shorting the sources in a similar manner.

 

[racecougar]

What happens at the transfer switch if current comes in at both ends?

A transfer switch will be break-before-make.

 

[Rusty Wrench]

The knife blade manual transfer switches I'm familiar with, rotate the same contacts through for both positions, so there is physically no way to connect the utility side to the emergency side... A good ATS uses a mechanical interlock that prevents shorting the sources in a similar manner.

Manual xfer switches depend on you to actuate.

Thank you for that. I wasn't getting the sense that the automatic ones couldn't have the same problem I already have.

I would replace the Challenger Panel...

These panels were/are on a recall list.

All You Need To Know About Recalled Electrical Panels

There are several well-known recalled electrical panels, which represent safety hazards and are dangerous to the integrity of the electrical circuits.

pennaelectric.com

Sparky #2 came by- or at least his estimator guy. He had a nicely colored book with a set price for each element; panel, switch and PIB. I gave him the history but didn't get the sense he was looking at it comprehensively. Just 3 separate work orders.
IDK, maybe that's how its done. But going to try a #3 before I commit.

This has been good. I have much clearer path of direction now.

 

[Firebrick43]

Thank you all for your comments. I took a little umbrage at being taken to the woodshed on my setup. But I totally acknowledge the inherent danger in the configuration as it exists. I have been reading and watching some YT to get to a better understanding of things.

Notwithstanding all the things that are wrong; I don't think I did anything wrong, per se. Gen off, gen cb off, main cb off- yet an audible fault. I don't run the gen full time during outs. Just enough to keep the food cold basically. I consider it luck the gen was not running when power returned.

Yes you did, stop trying to mitigate in your mind the danger you put others into !

Someone needs to fix you with a continued attitude like yours.

If you want to keep the food cold, use an extension cord from your generator to the fridge's cord directly.

 

[mm08822]

Yes you did, stop trying to mitigate in your mind the danger you put others into !

Someone needs to fix you with a continued attitude like yours.

If you want to keep the food cold, use an extension cord from your generator to the fridge's cord directly.

No question about the danger to lineman and even OP. But "licensed" Sparky#1 set the stage for this.........."He's a professional, so it must be right." He's the one that needs the trip to the sawmill!

 

[Metal-Marc]

OP needs a shock treatment.

 

[Firebrick43]

No question about the danger to lineman and even OP. But "licensed" Sparky#1 set the stage for this.........."He's a professional, so it must be right." He's the one that needs the trip to the sawmill!

No doubt about the sparky.

But Its not the OPs actions that so enrages me. Its after all the info in the thread that should have opened the OP eyes, he is still saying

"I don't think I did anything wrong, per se"

Ignorance is fixable with knowledge, and knowledge was presented/administered and it didn't cure him. Instead he took offense to being enlightened.

"I took a little umbrage at being taken to the woodshed on my setup. "

Neither of those sentences are from someone who realized they errored and will take steps not to do it again. And that attitude is unforgivable to the lineman and lineman's family who will miss him or have to care for him when he is killed or maimed.

 

[Innovate1]

The OP stated it was all done by a licensed electrician and people are calling out the electrician. I am wondering if the electrician made the suicide cord or had any knowledge of the intended use of the 30A circuit used to backfeed things. I haven't seen anything to indicate the wiring of the building itself has any issues that can be blamed on the electrician (other than the main panel which is a brand that is recalled). Sounds like the main breaker is only opening one side of the line and needs to be replaced ASAP.

Was the 30A breaker off or on when you got the loud hum from the generator? People are saying that breaker may also be bad but I didn't see anything stating clearly if it was off or on. That breaker is a reputable brand and unlikely to fail, although it is possible.

I don't see anything wrong with a properly installed breaker interlock on the main panel although the local AHJ may have rules about what is allowed.

 

[mm08822]

The OP stated it was all done by a licensed electrician and people are calling out the electrician. I am wondering if the electrician made the suicide cord or had any knowledge of the intended use of the 30A circuit used to backfeed things. I haven't seen anything to indicate the wiring of the building itself has any issues that can be blamed on the electrician (other than the main panel which is a brand that is recalled). Sounds like the main breaker is only opening one side of the line and needs to be replaced ASAP.

Was the 30A breaker off or on when you got the loud hum from the generator? People are saying that breaker may also be bad but I didn't see anything stating clearly if it was off or on. That breaker is a reputable brand and unlikely to fail, although it is possible.

I don't see anything wrong with a properly installed breaker interlock on the main panel although the local AHJ may have rules about what is allowed.

The OP reported the PIB cb is in the sub-panel and there is NO INTERLOCK in either panel! This is the situation Sparky #1 provided. Never discussed who made the cord. (My $$ is on Sparkey#1.)

 

[wyliesdiesels]

The OP stated it was all done by a licensed electrician and people are calling out the electrician. I am wondering if the electrician made the suicide cord or had any knowledge of the intended use of the 30A circuit used to backfeed things. I haven't seen anything to indicate the wiring of the building itself has any issues that can be blamed on the electrician (other than the main panel which is a brand that is recalled). Sounds like the main breaker is only opening one side of the line and needs to be replaced ASAP.

What brand of panel are you claiming is under recall?

Was the 30A breaker off or on when you got the loud hum from the generator? People are saying that breaker may also be bad but I didn't see anything stating clearly if it was off or on. That breaker is a reputable brand and unlikely to fail, although it is possible.

I don't see anything wrong with a properly installed breaker interlock on the main panel although the local AHJ may have rules about what is allowed.

What interlock are you referring to?

 

[mm08822]

The OP reported the PIB cb is in the sub-panel and there is NO INTERLOCK in either panel! This is the situation Sparky #1 provided. Never discussed who made the cord. (My $$ is on Sparkey#1.)

Furthermore, if a suicide cord is/was being used, that means the wiring device at the PIB is a receptacle and should have been a plug.

 

[Innovate1]

What brand of panel are you claiming is under recall?

What interlock are you referring to?

The OP stated it was under recall in post 23. I didn't verify that so I suppose I should have been more careful in my wording.

I was referring to an interlock that could be installed but is not yet in place. I am guessing you think I was saying there was one in the OPs case but I did not. Others in this thread have compared interlocks to transfer switches and stated their preference for transfer switches. I was just stating I think interlocks are ok. When properly installed of course. I guess the confusion may be I said "I don't see anything wrong with a ..." but I said "a breaker interlock" not "the breaker interlock". I could have avoided the word "see" I suppose. Sheesh. Seems like people like to jump to conclusions.

 

[BrandonV]

A tad off topic but relevant.

A long time ago I was helping someone who had a setup that involved a suicide cord, and I was trying to explain why the whole setup was a bad idea (he was aware not to touch the male plug).

What I always like to remind people is that regardless of if you are 100% safe (and comfortable) around a dangerous setup it doesn't take much for someone else to NOT be and injure or worse kill themselves.

I recall a story a while back about an angry neighbor who unplugged a generator that he found too noisy and zapped himself right on the spot because of the suicide cord. Have fun trying to explain that one to your home insurance or police.

 

[Innovate1]

Furthermore, if a suicide cord is/was being used, that means the wiring device at the PIB is a receptacle and should have been a plug.

It's not a PIB. It's a simple receptacle as currently done.

 

[wyliesdiesels]

The OP stated it was under recall in post 23. I didn't verify that so I suppose I should have been more careful in my wording.

I was referring to an interlock that could be installed but is not yet in place. I am guessing you think I was saying there was one in the OPs case but I did not. Others in this thread have compared interlocks to transfer switches and stated their preference for transfer switches. I was just stating I think interlocks are ok. When properly installed of course. I guess the confusion may be I said "I don't see anything wrong with a ..." but I said "a breaker interlock" not "the breaker interlock". I could have avoided the word "see" I suppose. Sheesh. Seems like people like to jump to conclusions.

Awww i missed that in 23 but ive never heard of a recall on challenger panels… still lots of them out there

 

[mm08822]

It's not a PIB. It's a simple receptacle as currently done.

You're correct. I didn't go back to the original post ....2 weeks is along time! Still the same point for needing a suicide cord.

I wonder if it 3 wire or 4 wire............

 

[ripperd]

What I always like to remind people is that regardless of if you are 100% safe (and comfortable) around a dangerous setup it doesn't take much for someone else to NOT be and injure or worse kill themselves.

I recall a story a while back about an angry neighbor who unplugged a generator that he found too noisy and zapped himself right on the spot because of the suicide cord. Have fun trying to explain that one to your home insurance or police.

That is a good point and the main driver on why I went the compliant interlocked breaker route.

I'm perfectly comfortable with myself using a suicide cord safely for everyone involved when I am present.

However, I won't be there to babysit the cord and generator all the time. And I'd like to be able to instruct someone how to hook things up and get the house going on generator if I happen to not be there. So I went the proper way with a fully compliant interlock kit, generator inlet, and standard cords/plugs.