sbridge2001

bucket truck grounding

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I need some help from any lineman. When working on an overhead line or transformer from a bucket truck, do you ground the truck to the earth before starting the work. If so, how safe does this make you if the bucket comes in contact with an overhead line.

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I need some help from any lineman. When working on an overhead line or transformer from a bucket truck, do you ground the truck to the earth before starting the work. If so, how safe does this make you if the bucket comes in contact with an overhead line.

You have to look at you safety rule in you area. Some place you have to ground the truck to the system neutral before doing any line work. Us here we don't ground the truck at all But the boom have two section insulated, one for the bottom boom and the upper boom is full insulated, we test them every 6 mounth :ernaehrung004[1]:

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I'm not a lineman. I'm an inside wireman. I'm trying to get this information for a safety class I'm working on. I want to find out if personnel can be protected if they ground the vehicle.

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Depends on the company rules, some require you to ground the truck others want you to "barricade" it so you should make sure your familiar with your company rules. But if you are going to ground it you would do so before working the line. Also if you have a retractable reel for your ground you need to pull the ground out completely. Under a fault condition the reel can self destruct with the ground still partially coiled resulting in total failure of your ground.

Now if the bucket makes contact and all other protection methods failed (rubber/plastic cover, blankets, fiberglass boom) and you had to depend on the ground then here's the kicker. The ground still does not protect you, its sole purpose is to activate the system protection be it a fuse, breaker, ext. The ground will take most of the fault current to ground threw the ground its self but electricity will take all paths to ground including tires, outriggers and a person touching the truck. So basically you hope the ground does two things; it limits the time and the amount of current that can flow threw your body by quick activation of the system protection but it doesn't remove the danger completely because you are still at a different potential.

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thanks for the info pappy, it will be very helpful

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Depends on the company rules, some require you to ground the truck others want you to "barricade" it so you should make sure your familiar with your company rules. But if you are going to ground it you would do so before working the line. Also if you have a retractable reel for your ground you need to pull the ground out completely. Under a fault condition the reel can self destruct with the ground still partially coiled resulting in total failure of your ground.

Now if the bucket makes contact and all other protection methods failed (rubber/plastic cover, blankets, fiberglass boom) and you had to depend on the ground then here's the kicker. The ground still does not protect you, its sole purpose is to activate the system protection be it a fuse, breaker, ext. The ground will take most of the fault current to ground threw the ground its self but electricity will take all paths to ground including tires, outriggers and a person touching the truck. So basically you hope the ground does two things; it limits the time and the amount of current that can flow threw your body by quick activation of the system protection but it doesn't remove the danger completely because you are still at a different potential.

I will also add that there will be a voltage gradient coming from anywhere that the electricity is going to ground. Whether it be from the ground rod, outriggers, the tires that more than likely will be blown out. That is another hazard because of the difference in potential radiating from those points on the ground. Some places make the groundmen wear dielectric shoes when working on the ground for that very reason.

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Grounding trucks is to protect people on the ground. The rule came out of the number of incidents where truck booms in contact with overhead conductors, because they were high resistance to earth, would not trip protective devices. Ground personell would touch the truck and die. Grounding the truck causes protective devices to trip so that the truck can not become "quietly" energized.

OSHA requires that if you ground trucks you also have to barricaded and prevent exposure to different potentials for people on the ground most often by placing ground mats. If you are looking in OSHA's 1910.269 it's the last rule in the truck grounding (p)(4)(iii)©.

Grounding does raise the hazard level for lineman in the bucket if he (or she) has not maintained the electrical isolation of the upper fiberglass section. A bigger problem is rarely identified even though OSHA discussed it alot when writting the rule. If you tie your truck to the system neutral or pole ground you are creating a parallel path to earth. If a fault occurs on the circuit even miles away, and your truck is between the fault and the substation, there is a possibility that the truck will become momentarily energized by fault current traveling on the neutral.

I do not let my guy's ground trucks except in special circumstances. I expect by guy's on the ground to look up before they touch the truck. It's safer for everybody.

I need some help from any lineman. When working on an overhead line or transformer from a bucket truck, do you ground the truck to the earth before starting the work. If so, how safe does this make you if the bucket comes in contact with an overhead line.

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Grounding trucks is to protect people on the ground. The rule came out of the number of incidents where truck booms in contact with overhead conductors, because they were high resistance to earth, would not trip protective devices. Ground personell would touch the truck and die. Grounding the truck causes protective devices to trip so that the truck can not become "quietly" energized.

Hey there Jim. I would have to disagree somewhat with the truck grounding being there to protect the guys on the ground. True, truck grounding came out to trip out the protective devices, but wouldn't it be safe to say that the truck will still become momentarily energized until the protective device trips out? A person leaning against the truck would still get hit with some lethal voltage. And yes, the guys on the ground should be paying very close attention to the location of the truck booms before getting near the truck.

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I WILL ADD, THAT THE VOLYAGE GRADIENT THAT TLW TALKED ABOUT, IS KNOWN AS .......STEP POTENTIAL.......IT WILL FLOW OUTWARD IN CONCENTRIC CIRCLES FROM THE GROUND ROD ......OR WHERE AN ENERGIZED CONDUCTOR IS LAYING ON THE GROUND..............DO NOT TAKE STEPS, AS IN LIFTING YOUR FEET OFF THE GROUND, IF EVER IN THIS SITUATION............SHUFFLE YOUR FEET.........IF YOU TRY TO WALK OR UN, THEN 1 FOOT MIGHT BE AT ONE POTENTIAL....AND THE OTHER FOOT AT ANOTHER POTENTIAL....THERE FORE A DIFFERENCE OF POTENTIAL IS CREATED, AND YOUR BODY WILL BECOME THE PATH FOR CURRENT FLOW :Voskl1[1]:

WE GROUND AND BARRICADE OUR DIGGER TRUCKS..............OUR BUCKET UNITS HAVE THE LOWER INSULATED FIBERGLASS SECTION, WHICH DOES NOT REQUIRE IT TO BE GROUNDED......SOMETIMES WE WILL GROUND THE BUCKETS, WHEN WORKING INSIDE AN EVERGIZED SUBSTATION THOUGH.........

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Let me clarify: You are right Texas, and I agree with you. The rule was created to protect ground personell but as you correctly point out it does not do that if someone is touching any equipment grounded if a fault hits. That's why OSHA and IEEE added the rule to require equipotential mats or some other assurances to protect folks on the ground. Before OSHA puts rules in place they hold indepth discussions recorded in "Preambles" In the preamble to the 1910.269 the committees extensively discussed how dangerous the truck grounding rule was and how absurd it was to be ignoring it for so long (since the 1974 creation of the 1926 distribution standard) A better way for me to state it might have been Grounding trucks is to protect people on the ground but only if they are not touching the equipment, or in close proximity to it, the moment it becomes energized.

Grounding trucks is to protect people on the ground. The rule came out of the number of incidents where truck booms in contact with overhead conductors, because they were high resistance to earth, would not trip protective devices. Ground personell would touch the truck and die. Grounding the truck causes protective devices to trip so that the truck can not become "quietly" energized.

OSHA requires that if you ground trucks you also have to barricaded and prevent exposure to different potentials for people on the ground most often by placing ground mats. If you are looking in OSHA's 1910.269 it's the last rule in the truck grounding (p)(4)(iii)©.

Grounding does raise the hazard level for lineman in the bucket if he (or she) has not maintained the electrical isolation of the upper fiberglass section. A bigger problem is rarely identified even though OSHA discussed it alot when writting the rule. If you tie your truck to the system neutral or pole ground you are creating a parallel path to earth. If a fault occurs on the circuit even miles away, and your truck is between the fault and the substation, there is a possibility that the truck will become momentarily energized by fault current traveling on the neutral.

I do not let my guy's ground trucks except in special circumstances. I expect by guy's on the ground to look up before they touch the truck. It's safer for everybody.

I need some help from any lineman. When working on an overhead line or transformer from a bucket truck, do you ground the truck to the earth before starting the work. If so, how safe does this make you if the bucket comes in contact with an overhead line.

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[quote name='sbridge2001' date='10 March 2007 - 10:16 AM' timestamp='1173550587' post='95815']
I need some help from any lineman. When working on an overhead line or transformer from a bucket truck, do you ground the truck to the earth before starting the work. If so, how safe does this make you if the bucket comes in contact with an overhead line.
[/quote]


Hey check out [url="http://www.buckettruckblogger.com"]www.buckettruckblogger.com[/url]. There is some info about safety with links to videos.

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Welcome to the site southwestequipment

Cool site thanks for the share!!!!


olo131

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should be relatively simple IF some1 knows how electricity behaves to ground ALL metal devices including cars/trucks/lifters/whatsoever when working close to power lines..

reason for this is induced electricity around metal objects, which can and sometimes will be lethal to living beings, aka men, thus pointing this induced voltage to ground is relatively safe method to keep working conditions to "nice" level, when taking something from the car for example and also purge the voltage away from metal objects to keep voltages to the level people dont get killed.. especially this kinda effect comes when youre working around (underneath) 110kV => power lines
its measured here that "cold" 110kV line can have induced voltage of 28500 volts, so this is the reason why cold lines are grounded before work is in effect, same effects can happen to other metal objects if theyre not properly grounded..

glad question came out and i see there is differend opinions on this one, but for those who say never ground ur truck, id say shame and shame again eternal shame, to give such orders to people which can lead to serious injury or even death.. read ur manuals and understand the text u read, electricity behaves similarly everywhere around the world, its just simple physics and math, not rocket science to understand, basic rules apply and one thing is to remove lethal voltage away from objects, people needs to work around, this is what grounding is used..

okay next thing some wiseass says about insulated booms and such, hell you can ground the chassis, without interfering the bucket insulation itself, inducion happens to every metal parts of a car and if you dont believe me, stop ur truck underneath 500kV line, remove ur shoes and hit ur **ck to hood of ur truck, and i bet you can feel the powah :P

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