using fish tapes into live panels

Status
Not open for further replies.

mike bridges

New member
A while back an electrician was sending a fish tape into a 20 ft. .75" e.m.t..
This panel was 277/480 and was believed to be locked out and safe. needless to say when the fish hit the main lugs the electrician was shocked and sent to the hospital. My question is why did the electrician get hit when the main over current device tripped when the snake fell between 2 phases?
 

eric9822

Senior Member
Location
Camarillo, CA
Occupation
Electrical and Instrumentation Tech
Probably because both lugs were not contacted at exactly the same time and because a circuit breaker takes 6 to 7 cycles to clear IF it is a solidly connected fault.
 

charlie b

Moderator
Staff member
Location
Lockport, IL
Occupation
Retired Electrical Engineer
Are you asking why he felt a shock, given that the OCPD had tripped and turned off the circuit? Or are you asking how he would be part of a current path, when current should be travelling only from one bus to the other?

I have two possible answers to the first question. One is that it takes time for the OCPD to react. You didn?t say how badly the person was injured. It is possible that he received enough of a shock that he could feel it, but the circuit tripped before the injury could have gotten worse. The other possibilities is that the tape did not go across two phases when it first contacted anything live. It may have touched only one phase at first, giving the person a shock, but without tripping the OCPD. Some moments later, perhaps due to a push or pull on his part in reaction to the shock, it may have come into contact with the second phase, causing the breaker to trip.

My answer to the second question is that current takes all available paths back to its source. One path, for example, is from one phase bar to the other phase bar, using the fish tape as a conductor. Another path is from one phase, via the fish tape, to the person?s hand, through his body to his feet, through the building into the dirt below the building, through the dirt to the ground rod, and up the GEC back to the source. True, current in the first path may be in the hundreds, or even thousands of amps, whereas the resistance of the second path is so high it will limit the current to below one amp. But a fraction of an amp is all that is needed to give a fatal shock.
 
mike bridges said:
My question is why did the electrician get hit when the main over current device tripped when the snake fell between 2 phases?

Even if he was touching the buss and NOT stuck at the stripped feed wire before the main, the response time for the OCP isn't long enough to protect the fish tape (btw plumbers use a snake not electricians) and the DUMMY holding the other end of a metal tape.

Work safe. Work smart.
 

480sparky

Senior Member
Location
Iowegia
mike bridges said:
A while back an electrician was sending a fish tape into a 20 ft. .75" e.m.t..
This panel was 277/480 and was believed to be locked out and safe. needless to say when the fish hit the main lugs the electrician was shocked and sent to the hospital. My question is why did the electrician get hit when the main over current device tripped when the snake fell between 2 phases?

Most likely, he didn't get to both of them at the same time, just one.. and that's all it took.

The tape may have gotten burned off between the terminal and the point where it was grounded, then the peice fell onto the other terminal.
 

chris kennedy

Senior Member
Location
Miami Fla.
Occupation
60 yr old tool twisting electrician
If I have a metal fish tape into 20' of EMT and hit a buss or lug, there will be fireworks but not on my end.
 

mdshunk

Senior Member
Location
Right here.
I have no idea how this happened
whistling2.gif


blownupconnector3.jpg
blownupconnector2.jpg


blownupconnector1.jpg
 

480sparky

Senior Member
Location
Iowegia
What I typically do is take a female-threaded PVC cap and install that on the connector. When my tape stops cold, I know I've hit the cap. Then I remove it and can pull the tape on out with needle-nose.
 

mdshunk

Senior Member
Location
Right here.
I guess people do the trick with a female adaptor glued onto a piece of smurf tube, screwed onto whatever connector threads are sticking out. Directs the fish tape out and onto the floor.
 

brian john

Senior Member
Location
Leesburg, VA
All I can tell you this is a common mistake, I have had more than my fair share of cleaning up messes from electricians running fish tapes into gear.

What ever method you use to avoid doing this DO IT.

Start with de-energized panels.
Fiberglass tape.
Smurf tube.
Pipe Cap.
Scotch 33.
What ever it takes.
 

76nemo

Senior Member
Location
Ogdensburg, NY
dSilanskas said:
They make a nice fiberglass fish tape

I can't bash anyone who got hit with juice. He was told it was LO/TO'd, but I am not using steel without gloves. I wouldn't use steel with any existing service. I'll use gloves even with fiberglass or nylon.

Gloves and proper footwear or nothing! Safety first. He/she could of left on a sheet covered stretcher.

This is a classic story of why we don't do what we shouldn't. This was WRONG all the way around. The victim learned a hard, HARD lesson.

There is NOTHING to question on being too safe.
 

electricalperson

Senior Member
Location
massachusetts
mdshunk said:
I guess people do the trick with a female adaptor glued onto a piece of smurf tube, screwed onto whatever connector threads are sticking out. Directs the fish tape out and onto the floor.
thats an incredibly good trick never heard of it before. usually i use a fiber glass snake or blow a string in
 

peter

Senior Member
Location
San Diego
Was the fish tape damaged?

Perhaps the lock out/tag out was the main breaker in the panel itself, thus its feeders would still be energized. I've seen dis-connects that have plastic covers over the line terminals. Why don't the manufacturers make the same type of covers to "protect" the terminals in panels? Hasn't anybody thought of this?

Given the choice, it would be better to push the fish tape from the panel instead of into it.
~Peter
 

mxslick

Senior Member
Location
SE Idaho
Umm, like no way.. :

Umm, like no way.. :

peter said:
<snip>

Given the choice, it would be better to push the fish tape from the panel instead of into it.
~Peter

I strongly disagree with that statement. First off, that puts you working directly in front of the panel (Let's not engage the arguement of you shouldn't be working on it if it's live or not for now) and the possibility of the length of fishtape you're pushing on/pulling on can get unruly and contact things that are bad for your health. :)

I'd rather be feeding the insulated conductors from the panel end, less possibility of any kind of metal-to-buss contact.

The OP's situation was unfortunate. It seems that assumptions were made that proved to be wrong, with some bad consequences.

ALWAYS verify that power is off yourself, I never trust anyone else's word that it is. Check it before you start work.

APPLY you OWN LOTO to the disconnects/breakers/etc. Threaten to break the fingers of anyone who tampers with or removes your LOTO. (I've had to do so on a few jobs.)

TRY to only use non-conductive fishtapes when you have to push into any panel, energized or not. If you don't have a nonconductive fishtape, the smurf tube and other suggestions given here will lessen the chances of accidents.

Thankfully in my line of work I do not have to ever work in any energized panels or switchgear. I do, however, deal with the subpanels built into some makes of projector consoles and also have to deal with the HV hazards of the Xenon lamp ignitors. A hit from one of those ignitors will numb you arm for a full day. :roll:
 

don_resqcapt19

Moderator
Staff member
Location
Illinois
Occupation
retired electrician
I can't bash anyone who got hit with juice. He was told it was LO/TO'd,
Being told something is locked out doesn't count. The worker has to put his own lock on the energy source or in the case of a group lockout he has to verify the lockout and then put his lock on the group lock box.
 

76nemo

Senior Member
Location
Ogdensburg, NY
don_resqcapt19 said:
Being told something is locked out doesn't count. The worker has to put his own lock on the energy source or in the case of a group lockout he has to verify the lockout and then put his lock on the group lock box.


Ohh, fully agree Don. I just can't bring myself to say anything negative to an individual that got nailed unless they ask me my advice or continue to doing somethings deemed unsafe. That's what I meant. What I really meant, is I am glad he/she is still alive!!!!!!!
 
Status
Not open for further replies.
Top