Digging Around Energize Primary

[rnewcomer]

I would like to hear from all you out there your opinion on exposing energized underground cables. Do you do any hand digging to expose them and if you do what precautions do you take. Or, do you only expose cables after de-energizing them.

Rich

[BigClive]

In the UK if you hit warning tape while using a backhoe (JCB) then you immediately switch to digging carefully by hand.

If there are known cables in the vicinity either through maps or sensing then the backhoe breaks the surface and it's hand digging from there.

[T-Man]

If the cable is energized we have to hand dig wearing gloves,and overshoes,
company rules.

[CHICAGO HAND.]

Rubber Gloves And Fr. Soon To Come Are 20 Kv Overshoes.
Any Prefab Primary Voltage Urd Joint You Uncover Must Be Taken Out Of Service And If One Phase Faulted And The Other Two Are Spiraled With It They Must Be Taken Out Also. 24 Inches Is As Close As We Can Get With A Machine. Illinois Locate Laws State That A Jack Hammer Or Similar "hand" Tool Can Be Used Within The 24 Inch Zone. I Will Leave That Work To The Law Makers To Show Me How That Is Done. I Have Hit My Share Of 600 Amp 12 Kv Feeders To Know That I Would Rather Be On A Machine Than Staring Down At The Tip Of A Jack Hammer. We Expose Energized Primary Every Day And Alot Of Times Its For A Cut Over That Requires One Open To Deenergize But Management Would Rather Take The Risk And Put Us In Harms Way Rather Than Do The Open Before We Dig. Nice Guys Ha.
And Dont Get Caught Hitting Something Within The 24 Inches With A Machine They Will Put You In The Box For A Few Nights.

[NU Limey]

We hand dig when near any line, by the time any backhoe would feel the nudge it would be too late. digging by hand is also done very carefully. common sense don`t step on top of the spade and push with all your weight

[Bigheadnc]

Wow, I WOULD DEFINATELY PUT IT ON ONE SHOT.

[Trampbag]

Wow. Overkill. Gloves and overshoes? I can understand hand digging around cable, but come on…

I might be able to understand this if the cable were direct buried low voltage lead/paper, or perhaps direct buried plastic covered 600 volt secondary or maybe even 2300 volt where no concentric exits, maybe. Is there any unarmoured direct buried lead/paper cable anymore in the industrialised world???


All the cable I ever dealt with in the UK was armoured, much like sub-marine cable in North America, and although much is direct buried (I never see any in duct) it would be difficult to penetrate the armour with an axe. I wouldn’t want a JCB to hook it though. It would break connections on the terminations.

Concentric cable is not hazardous to handle. Neither is lead/paper when in good condition. Reasonable precautions are required, but jeese gloves and overshoes.

[dwalla-walla]

If it is hot ud secondaries the we have to wear overshoes and use a tool with a non conductive handle. All of our shovels and stuff have fiberglass handles. Same with primaries but we almost always deenergize them first.

[A Laska Lineman]

When we excavate around utilities( power, gas, communication or cable TV), especially in congested areas, we use an "air knife". This device is a 10' piece of 1" pipe with a 90 degree elbow and shut off valve, that is attached to a 250cfm (or more) air compressor. We are not allowed to dig within 2' of a locate and we must have locates to dig. We will dig a hole next to what we are looking for, deeper than what we are looking for, and blow into it. When the deep part fills up, dig it out and fill it up again with blown dirt. It saves alot of time, easier on the back, and safer than with a digging bar or pointed shovels. We do not de-energize just to expose primary or secondary cables. We do not handle U/G energized primary cables with-out rubber gloves and PPE. And we are extra cautious with splices, new and old. Here we use a jacketed U/G primary cable, being either concentric neutral, wire-shield, or tape-shield. On the North-Slope they use CU Armour Cable(10lbs/ft) to feed the drilling rigs. You can make an "air knife" for under $50 from your local hardware store. Beat the end of the pipe, almost closed, for more pressure and make sure the shut-off valve is at the 90, so that you can turn it off quickly. Hearing protection, gloves (the pipe gets hot) and a face shield are a must. The rubber part of a toilet plunger works good, if hose clamped about a foot up, to prevent some of the dirt and rocks from coming directly back at the operator of the "air knife". It is a dirty and noisey job but it saves alot of time, which is money, and no cables are damaged. A factory built "air knife", back in 1988, cost about $1,200 and I have no idea what they cost now. They work good in sand, gravel, and dirt. but they don't work good in clay or peat. Try not to jab the dirt, and know when to quit and use a shovel. Try it you'll like it.

[lewy]

if it is an emergency & we do not have time for locates we will use a sucker truck that digs the hole with water. a high pressure hose breaks up the ground & the vacum sucks it up . it does not damage the plant & is very quick. they still wear there rubber gloves when doing this.

[poletop22]

[QUOTE=Trampbag

I might be able to understand this if the cable were direct buried low voltage lead/paper, or perhaps direct buried plastic covered 600 volt secondary or maybe even 2300 volt where no concentric exits, maybe. Is there any unarmoured direct buried lead/paper cable anymore in the industrialised world???
[/QUOTE]

Yep we do have alot of paper lead and even oil filled cable around the local utility hires cable joiners from the UK to come over here and work. The stuff hasn't been laid for years so the do transition joints whenever they can usually for new pole terminations and replace then dodgey old cast iron cable heads that have a real nasty habit of exploding like a fragmentation bomb when re-energised...

[linescum]

i have been dealing with digging underground faults exclusivly now for 3 years pri and sec, we use a vac-n-dig excavac rig and an air knife works great break the dirt with the air and suck it out with the vac make your repairs and the dump your spoils back in an tamp.. we can usually repair a secandary fault in 3 to 5 hours that include locating and restoration, imho it's the only way to go on energized urd excavation. plus use can suck all the garbage out of your truck:)

[scammy]

ive been doing this a few days myself,,,remember one thing,you are alreaddy grounded,,,be carefull ,,and dont listen to the dumbasses that tell you ,you take to many precautions,,and always test what you touch,and ground it ,scammy