One Shot Theory and Operation

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10-20-2020, 05:17 PM
Reddy_Kilowatt

Hot Line Tag: Theory, Operation, and Industry Standards

I have a manager which is looking for some guidance of "Hot Line Tag". He would like to know more about industry standards of the operation.

I have mentioned to him, the hot line tag operation will operate within 3 - 5 cycles of a fault. This opening operation could save a life in case of a contact. He is inquiring more for the industry's practices, standard working procedures, other utility work practices, and other information of the one-shot theory and operation.

The thoughts are:
1). Thinking line crews' covering -up work procedures could be reduced....
2). Crew may become complacent, depending on the hot line tag to open in case of poor work procedures
3). Maybe only use hot line tag if you are gloving within minimum approach distances.

I would appreciate your thoughts…..please share.
10-21-2020, 03:20 PM
Lineman North Florida

The first thing most company's are going to tell you is that automatic reclosers being placed in one shot is for protection of equipment and not to be relied on for the protection of lineman, with that being said I have never met a lineman who thought if there was a problem that 2 more shots was a good thing, myself included. Some company's won't give you a one shot unless you are working on mainline feeder and yet due to breaker settings if you are working behind 140 amp fuses it will operate the station breaker once before blowing the fuse, as far as lineman counting on the one shot to keep them out of trouble, I hope not, that sounds like something that a manager who has no background in line work. What are your current procedure for getting a one shot?
10-22-2020, 09:13 PM
Orgnizdlbr

Quote:

Originally Posted by Reddy_Kilowatt

I have a manager which is looking for some guidance of "Hot Line Tag". He would like to know more about industry standards of the operation.

I have mentioned to him, the hot line tag operation will operate within 3 - 5 cycles of a fault. This opening operation could save a life in case of a contact. He is inquiring more for the industry's practices, standard working procedures, other utility work practices, and other information of the one-shot theory and operation.

The thoughts are:
1). Thinking line crews' covering -up work procedures could be reduced....
2). Crew may become complacent, depending on the hot line tag to open in case of poor work procedures
3). Maybe only use hot line tag if you are gloving within minimum approach distances.

I would appreciate your thoughts…..please share.

First and foremost, under no circumstances should a line crew reduce cover up procedures because some manager in an office thinks disabling reclosure operation is a safety procedure PERIOD! Whenever we disabled the reclosure and put the breaker on instantaneous trip, there was a possible hazard involved AND THE WORK COULDNT BE ACCOMPLISHED DE-ENERGIZED. When a breaker operates, even with the instantaneous trip operational, the breaker WIL NOT OPEN UNTIL THE PICK UP AMPS ARE SEEN BY THE OVER CURRENT RELAYS. Many distribution breakers where I worked were set at 900 pickup amps, that’s an awful lot of available fault current to eat, have your face in, or your pole partner’s face in. Lastly, I have no idea what you mean when you say “This operation could save a life in case of contact”. What protection does a single breaker operation give a human in contact with a primary?
10-23-2020, 05:11 AM
rob8210

NEVER, rely on one shot ( we call it blocking the recloser in Canada) , it is not designed or intended to provide any protection to a lineman . They do fail as well. Proper coverup and safe work procedures is the only thing a fella can rely on. I personally do not trust anyone or anything but myself, and I make mistakes too! It’s true that one shot will only electrocute you once , not 3 times , if it is working properly. Are they even maintained regularly? I know ours aren’t.
06-28-2021, 01:04 PM
DaddyBruce

Single shot is an obvious normal for all line crews working in proximity and others.

The normal practices are to have the line protection in single shot. It is only line protection as for linemen protection your work procedures and cover up or limits of approach can only help. The personal protective gear as in fire retardant gear and all other barriers indoor or outdoor can only give limited relief in an explosion! Do not go there. Too nasty to discuss.