1. #1
    HYTHE FIRE DEPARTMENT
    Firehouse.com Guest

    Post Electricity and structure fire fighting

    I belong to a small rural fire department in Northern Alberta. When we respond to a house fire in the county, we never have a concern about electrical hazards inside a home as the power is shut off at the pole near the entrance to the property. In the town that we cover, this is a different story as there is no external power shut off, only a meter.

    Some of my members are concerned about spraying water inside a house that still has live power. Although I have been informed by our poer company and some electrical engineers that it is safe, I am not so sure. In any case, we always call the power company to come turn of the power. But in the mean time we continue to fight the fire even though the perceived hazard is there.

    What does your department do when called out to a structure fire? do you mess around with removing the meter? do you carry on until the power company arrives?

    John

  2. #2
    Steamer
    Firehouse.com Guest

    Post

    John--
    I would imagine the electrical services in your area is similar to here in the US, so the same things should hold true. If you are currently removing the meters at your structure fires, you should immediately stop. There are basically 2 reasons for this.
    Reason #1: If you ground the legs of the meter to the meter box, or any other similarly grounded material/object, you are at great risk of injury when the meter explodes. Imagine a glass hand grenade going off in your face, and you'll have the picture.
    Reason #2: There is no guarantee that the power is off when you remove a meter. Not all meters have the power run through them. Many work like an amp meter, and measure the power using an induction coil. You might have gotten the meter out of the meter box, but it has in no way interrupted the flow of electricity with this type of meter.
    We carry the proper equipment and received the proper training from our power company that allows us to cut the power at the drip loopes at the entrance mast. As this is dangerous in itself, we don't do it unless we absolutely have to. Our other option is to wait until the power company arrives to shut off the power. That's still the safest and surest method.
    You might also shut the power off at the main breaker in the electrical box, unless of course it is involved in fire, and damaged.
    Again, you should immediately stop pulling the meter to disconnect the electrical service. The risks far outweigh the benefit.


    ------------------
    Steve Gallagher
    Chillicothe (Ohio) Fire Department

  3. #3
    BFD 210
    Firehouse.com Guest

    Post

    Very interesting reading as far as water and fire streams is in the NFPA Fire Protection Manual. It has some good test data that they have done on both fog nozzles and smooth bores and how far electricity will conduct with them. I agree with steamer that pulling the meter is extremely dangerous, eventhough my dept still does it. I think the main hazards are of course exposed wires you can contact going in and when overhauling.

  4. #4
    mtnfireguy
    Firehouse.com Guest

    Post

    As has been said... dont pull the meters, call for the power company to kill the power.

    We are finding more structures in rural setting have a master disconnect, but this is not the norm.

    We teach to dispatchers to notify the proper power company upon confirmation of a working fire. If for some reason they arrive and the power doesnt need killed, well.... they go home. Kinda like call mutual aid, better to have them coming and not have to wait longer than necessary

  5. #5
    KEA
    Firehouse.com Guest

    Post

    Great Post!!!
    PART 1 of 2
    I try to live by a standard that is simple and effective. Simply ask the question, Says Who, and With What Proof? This question seems to get to the bottom of the information I'm looking for. It can be applied to any aspect of your life. For others to tell you what they do may give you some comfort, it may not expose the true dangers involved

    I would encourage you to get your hands on a NFPA Fire Protection Handbook and look up the section titled, " ELECTRICAL CONDUCTIVITY OF WATER" and "Safe Distances from Live Equipment".

    This is a brief exert for your benefit.
    Water in its natural state contains impurities that make it conductive. If water is applied to fires involving live electrical equipment a continuous circuit might be formed which would conduct electricity back to the user and cause a shock, especially if there are high voltages or potentials. Foam-type extinguishing agents are ver conductive. The amount of current, rather than the voltage, determines the extent of the shock. Principal variables, assuming contact with a live electrical charge, are:

    1. The voltage and amount of current flowing.
    2. The "break-up" of the stream as a result of the nozzle design, the pressure used , and the wind conditions. This break-up influences the conductivity of the stream because the air spaces formed between the droplets interrupt the electrical path to ground. Modern water spray nozzles and combination straight-stream spray nozzles, the latter in the spray (fog) position, provide for effective dispersion of the water droplets. The hazards of these are less than those of a solid stream of water.
    3. The purity of the water and the relative resistivity of the water.
    4. The length and cross-sectional area of the water stream.
    5. The resistance to ground through a person's body as influenced by location (whether on wet ground or not), skin moisture, the amount of current the body can endure, the length of exposure to the current, and other factors, such as protective clothing.
    6. The resistance to ground through the hose.

    Kirk Allen
    First Strike Technologies, Inc.


    [This message has been edited by KEA (edited January 06, 2000).]

    [This message has been edited by KEA (edited January 06, 2000).]

    [This message has been edited by KEA (edited January 06, 2000).]

  6. #6
    KEA
    Firehouse.com Guest

    Post

    PART 2 of 2

    The Toledo Edison Company made test in which water was discharged onto a screen at a potential to ground of 80,500 V. As a consequence, the Edison Electric Institute in 1967 adopted the following safety rules (the distance in these rules will limit leakage currents to less than 1ma).

    1. Using all hand-held water spray nozzles, the minimum approach distance is 10ft (3m).
    2. Using hand-held , 1 1/2-in (38mm) straight (solid) steam nozzles, the minimum approach distance is 20ft (6m).
    3. Using hand-held , 2 1/2-in (64mm) straight (solid) steam nozzles, the minimum approach distance is 30ft (9m).



    [This message has been edited by KEA (edited January 06, 2000).]

  7. #7
    DD
    Firehouse.com Guest

    Post

    I have seen a meter that had exploded. Yes, it was like a grenade. A lot of flying glass and flame. The homeowner who was fooling with it was very lucky. He received hand and facial cuts and burns. His glasses protected his eyes from the blast. I know that a lot of meters are pulled. Some disconnect the current and some do not do so. I will not do it and will not direct another firefighter to pull a meter.

  8. #8
    STBURNE
    Firehouse.com Guest

    Post

    KEA- don't forget that on the Toledo test, the voltage that water was applied on was 365 times the amount you will find in the average home. The safety distances in real firefighting situations are much closer than what the Toledo test gave us.

    Also, has anyone ever heard of a firefighter injured by directing water on live wires?

  9. #9
    HYTHE FIRE DEPARTMENT
    Firehouse.com Guest

    Post

    I guess my main question is, what do you do while the power company is on its way. We used to pull the meter, but we have stopped that several years ago. Our power company is about 20 minutes away from our town. They are always dispatched when we are dispatched to save time. But I still want to enter a house and fight the fire when the power is on. Is there a great risk for example to spray water in a living room that has live plug-ins, light switches, light sockets and electronics?

    In most cases if the fire is contained, I would send some one to try and find the panel if it was safe. But in some instances it might not be safe to find the panel. What is a man who has a very low resistance to electricity to do. My wife will kiss me on a dry winter day, and the static shock will drop me. I am glad she knows CPR.

  10. #10
    Steamer
    Firehouse.com Guest

    Post

    In 28 years of interior firefighting operations, I have never received an electrical shock nor do I know of anyone that has. Although the potential exists for the water to contact the live switches, and etc, the other variables are such that the risk of serious electrical shock is minimal. I know that we shouldn't bet our lives that the electrical systems are code compliant, but modern systems with proper sized breakers/fuses will generally drop the circuit before any serious risk is presented.
    I wouldn't necessarily go in and start handling exposed wires without shutting the power off, but I wouldn't be too concerned about incidental contact during the circumstances you describe.

    ------------------
    Steve Gallagher
    Chillicothe (Ohio) Fire Department

  11. #11
    KEA
    Firehouse.com Guest

    Post

    STBURNE
    Couldn't agree with you more!!!!

    Kirk Allen
    First Strike Technologies, Inc.

  12. #12
    Ten8_Ten19
    Firehouse.com Guest

    Wink

    Hey Hythe FD, that's quite a kiss! Nice to hear of couples who still know how to keep that old spark alive in their marriage.

  13. #13
    Boothby
    Firehouse.com Guest

    Cool

    The truck company driver's first job is to secure the utilities, both power and gas. During fire school we all go out to the Memphis Light, Gas, and Water training center and learn how to properly pull a power meter. We also carry the special key and equiptment to do so. About seven months ago we had a firefighter who recieved a minor electric shock fighting a residential structure fire where the utilities had not been pulled. I don't know the exact circumstances because I was working on two civilians in cardiac arrest, on the front lawn. Finally our dispatch automatically calls for a MLGW light man whenever we have a working fire. He usually caps the meter and double checks what we have done.

    ------------------
    Larry Boothby
    Firefighter/Paramedic
    Truck 3 A-shift
    Local 1784
    Memphis.

  14. #14
    Steamer
    Firehouse.com Guest

    Post

    Larry--
    Our local power company (AEP) won't even consider that in our area. They say they won't accept the liability. They feel it's safer to cut the drip loop. I wish we at least had the option to pull the meter. There's nothing wrong with it if you have the proper training and equipment, but no one in the AEP region has either that I'm aware of.

    ------------------
    Steve Gallagher
    Chillicothe (Ohio) Fire Department

  15. #15
    hfdCapt66
    Firehouse.com Guest

    Post

    i work for the local utility as well as vol ff-first to address some of the replies-i wouldnt pull a mtr at a fire scene unless i had my electrical safety equipment-which is tested every 2 months- same is true for cutting the drip loops-reason being that if you get into trouble- the only fuse protection you have is on the pole-usually rated in the 1000's of amps,and the transformer sees you as a load-it will pump all the power it can to you til the fuse blows-my advice from someone who's seen electric explode from too close- don't go there-you're playing roullette.
    As for the reply about protection in the panelbox- it only takes 1/4 amp to kill you if conditions are right(wrong) and most breakers are 15 or 20 amps.
    We have 4 utility workers who are ff's and we won't pull mtrs or cut drip loops(for what it's worth)
    what we do is send 2 ff's to the panel box-preferably one with electrical experience, to shut down the main breaker or shut off all the breakers.
    the national electric code requires the electric to have a shut off within 10 feet of entering the building-and it has to be able to be completely shut down by turning off no more than 7 individual breakers
    spraying water at that voltage is ok in my opinion- the power will travel to ground and trip-it will not travel across the floor-although you dont want to stick your hand in an outlet box-
    another quick thought- what about liability- if you think you have the power off, its not and god forbid someone gets hurt?

    [This message has been edited by hfdCapt66 (edited January 11, 2000).]

  16. #16
    Phred
    Firehouse.com Guest

    Question

    Larry B:

    Can you explain what procedures MLGW teaches you to follow and what equipment they give you? Do they instruct you Not to pull a meter in certain situations?

    Our local power company reps often pull residential meters using nothing more than leather work gloves for protection. I'd like to learn how they Know when it is safe to do this.

  17. #17
    Scene25
    Firehouse.com Guest

    Exclamation

    Well, my opinion on electricity. I am a firefighter, not a utility worker, therefore, I will not shut off the electric. And there have been many instances where electric being on was a good factor on a structure fire, for visibility. If the place rocks, then you will most definately lose the power. But, as soon as the confirmation of a working fire is made, the utility companies should be notified. I will never play with electricity, nor will I tell someone other than the power company to kill the electric. I have heard various problems that can occur if you pull the meter yourself. This is a dangerous operation itself, because once the meter is pulled, people assume the power has been definately terminated, which is not always correct. We dont want the power company inside a structure when we are doing our job, therefore, we shouldnt be performing their position. This is my honest opinion. Take Care and Be Safe

    ------------------
    John Williams
    NRFF1/EMT
    Clairton Fire Dept

  18. #18
    Steamer
    Firehouse.com Guest

    Post

    hfdCapt66--
    In your post you referenced the capacity of the breakers. I reviewed the posts and am guessing it is reference to one of my earlier posts. I probably should have been more clear in that I wasn't referencing the function of the breaker if an individual should contact the circuit. I couldn't agree with you more about the power needed to cause the breaaker to trip, but what I was talking about was the potential of the breaker to "kick" on circuits which have been fire damaged and faulted to short/ground and potential exposure to live heavily fire damaged wires. I have never had any problems under these circumstances.
    I just need to clarify my earlier post, and apologize for any confusion.

    ------------------
    Steve Gallagher
    Chillicothe (Ohio) Fire Department

  19. #19
    hfdCapt66
    Firehouse.com Guest

    Post

    steamer-
    no problem- i thought thats what you meant- i just wanted to clarify so no one misunderstood.
    I get concerned because,at least in my area,- people tend to become complacent around power, and it can turn on you too fast-without warning-as i'm sure we all know.
    be safe

    Scene25- GREAT point of view

  20. #20
    hellcat609
    Firehouse.com Guest

    Post

    The first thing we do is have dispatch notify the electric company as we are enroute if it is a structure fire. We can always cancel them if we dont need them. Second, first company on scene checks for an exterior shut off if there is one. If not we do what we have to do till the power company is there. I was on a structure fire 2 nights ago, we were doing an exterior attack through a rear window untill we had a team ready to enter, we were spraying water with a 1 3/4 when something popped all of a sudden. It was electrical. Later when the power company got there we found that the water had hit an exposed wire and actually tripped the fuse on the light pole. The power company was very happy in that they didnt have to do anything. We never remove meters though.

  21. #21
    DD
    Firehouse.com Guest

    Post

    Here's a horror story from a church fire involving electricity. Lightning had started a major fire in a large rural church. We responded on a mutual. The power company sent a line crew to disconnect the power at a line junction on a pole in front of the church. The wires then ran behind the church to a transformer bank on two poles. This was 7,800 volt primary current. The linemen apparently were more interested in the fire than they were in their work. This was discovered when a hose stream caused arcing and after the linemen had left. It seems that they disconnected the line that ran in the opposite direction, up a long lane to a farm. We were lucky that it did not cause any injuries. The language used had never been heard in Sunday school.


  22. #22
    DD
    Firehouse.com Guest

    Post

    Double clicker, sorry.

    [This message has been edited by DD (edited January 15, 2000).]

  23. #23
    STBURNE
    Firehouse.com Guest

    Post

    BOOTHBY-How minor was this firefighter injured, and was he flowing water or did he come in contact with the electricity?

    Has anyone ever heard of a firefighter seriously injured by flowing water onto live lines in a structure fire? I would be very interested in finding out, I don't think such a case exists.

  24. #24
    Ledbelly
    Firehouse.com Guest

    Post

    Guess I can add to the can of worms, as it looks like Boothby and I are alone on this.

    We also have a crew designated to pull the meter on residential fires; we won't mess with the commercial meters. At apartment complexes... it's a maybe, depending on how the complex has their meters set up. We've also had the local utility come and demonstrate/explain, so no one is flying by the seat of their pants. At a major fire, the utility is notified anyway.

    I've never personally seen any problems with flowing water in the interior before the power was cut; HOWEVER, I was present once when a guy in the interior got tangled up in a "nest" of wires and although I thought all the little blue fireflies floating around him looked pretty cool, I woke up when I heard him yelling for help. [Glad to have those side cutters in my pocket!] And, BTW, we had two guys get knocked across a room once... but they had jammed the nozzle up into the attic and evidently hit some wires. Neither one was seriously injured, but one was transported for evaluation.

    We've had the same problems before with the house still being "hot" even though the meter was pulled... so utility is usually sent to structure fires. When I started in 85 we were pulling meters, then quit doing it for awhile... and are back pulling them again... with the class given by the utility.

  25. #25
    DD
    Firehouse.com Guest

    Post

    About a year ago we had a fire in a corner of sides 2 & 3 bedroom and attic of a single story residence. After the extinguishment we found a wiring mess which did not cause the fire and was in other rooms. The breaker panel was on the front interior wall of a bedroom on side 1. It's cover was off and a #6/2 with ground wire was connected to a 50 amp, 240 volt breaker. The breaker was in the on position. The wire ran down the wall, along the floor of the bedroom, through a doorway, across the corner of the living room, through another doorway, and into the kitchen. In the kitchen, an aluminum pressure cooker was setting on the floor by a wall. Behind the pressure cooker was the end of the wire. It was connected to the cord of an electric range. The wire did not have a range receptacle on it. The wires were twisted around the blades of the male cord end. They were bare, with not even tape covering them. We we sure lucky that the hose crew did not crawl into that room and push the pressure cooker into the wire & cord connection.

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