Our company is pulling in the service cable for a hotel. The city is requesting that we do it "live" as there is a "famous coffee/donut shop" being supplied by the same padmount transformer. We could use some advice here. We fully expect the city to provide all necessary PPE and safety equipment. The high side voltage is 25KV.
The city must be isolating the high side with a barrier of some sort right? What would they use? I just want a little background info before I meet with the city tomorrow morning.

The HV side of the pad mount transformer already has a barrier seperating it from the LV side and the HV door can remain closed. Whoever owns the transformer be it the city or a utility company the people who do the power work must be involved and can assist in the safety proceedures and equipment. All exposed live parts in the LV side should be covered with insulating blankets.

Roger

[This message has been edited by Roger (edited 04-28-2005).]

Even without seeing the setup, this sounds very scary. Imagine what could happen if the rope breaks or comes loose from the wire. It's bound to tear up any rubber blankets and come into contact with something hot.

With the available fault current at the transformer you should probably take the same precautions OSHA is requiring now when working in a hot panel (fire retardant clothing, face shield, moon suit, etc.

For the record, I agree with Bill.

Roger

For the record I disagree with the whole thing.

OSHA does not permit this at all, PPE or not. I think you should appear before the city council and inform them that they are requesting you to directly disobey an OSHA regulation.

Pulling into a live transformer sounds like a great way to get yourslef killed.

here in this area we dont allow any pulling wire when the transformer is engerized and it is not safe.

i did talk to my freind he work for POCO and he say no freaking way [ i have to deleted cussing words here ] due the falut current. it will be mind bogging if you see that flashover it will do wonderfull damage
in that area and anyone who is standing by near transformer can get hit by flying deberies of moten metal, cables , plastic insluators , transformer oil [ of course ] etc etc.

i will suggest that talk to the city personalles to say this is not a safe way at all

to bring other cable to the transformer is best way is shut down or dengerized the transformer and pull new cables there and the same time can rent a generator for tempory power during that time peroid until it is done . c'est simple

Merci, Marc

If you can feed from the transformer end and have all hot lugs covered I don't see a problem with it.

On the other hand if you have to pull from the transformer I agree...no way.

This is a perfect time for a planned outage.
We do them all the time. Find a date & time that the other Customers are closed, & set it up to work de-energized.

"The city is requesting"

That means you can tell them no.

The power company sets the safety standards. I expect they will shut the power off when you need it off.

I got to reply to this, I can see where most would see this as a big no way, and the people that said this is a OSHA, you positive of that? I worked for the electric utility myself and at one time did also do the dist. work that your refering to a pad mount here. and someone mentioned that there is a barrier allready there (that is correct) and there most liky even 2 doors and the one with the primary behind it can remain closed. as for rules that the POCO would kill the pad mount to do the work I really doubt it, its done all the time hot (energized)... now the POCO I worked for would be doing all the work involed at the pad mount to a the meter, but in my area there is another utility that the EC pulls the conductor into the pad (with it energized)(and I have done this pulling into there pad mount's bye myself even as a EC) they do require that you show proof of insurance and your ELECTRIAN LICENSE before they give you the key/combination's to the pad mounts. and there is another city owned utility bye me that is allmost the same way no standards or rules at all. well had to give my 2 cents,,, but you did say PPE was being provided, so sounds like you should have what you need to get this done, there will be rubber blankets with big cloths pins type clamps, another way of putting it is Electric bussiness has got dangers, if the world didn't need electricians, you could grab anyone to do that....

[This message has been edited by highvoltageguy (edited 04-28-2005).]

I could be wrong but, I believe that this work could "legally" be performed but according to NFPA 70E all of the required personal protective equipment would have to be worn by anyone working within a certain distance of the live parts and it would be "Permit Required" work. Which means, the city would have to sign a form stating why the work would have to be preformed live and usually loss of proffits is not a consideration.

By the city signing this form, most, but not all, of the liability would be shifted to the city. Avoid doing the work live if at all possible. Do not under any circumstances do the work live if the city will not sign off on the permit. If the work is done live you will need an engineer to calculate the energy of the possible arc blast to choose the proper personal protective equipment.

Safety First. Remember, we all want to make money but if we can't go home to our families at night or if we are permanately injured no amount of money will matter.

Good luck.

bill,
I'm with master66 on this one.
Other side of the coin, having a "famous coffee-house" on the end of a HV transformer sounds like a pretty lame excuse for doing work live.
After all, can't it be done at night?.
There is no such thing as no time to "do it dead".
Regardless of the arc flash hazard caused by short-circuit, I'd be concerned with any flash-over distances that these voltages have.
I'd be asking the PoCo about this before the work takes place, after all it is their equipment.
A general "rule" over here in NZ is that all HV gear be de-energised and Earthed (Grounded) before staff are allowed access to the conductors.

NFPA 70E clearly states that you should not be doing this live. The only way it would be allowed is if shutting the power down would jeopordise life. Now I know a lot of people "think" they need coffee to survive, I don't think that that is what the NFPA is referring to. They are referring to life support in hospitals. And I'll tell you, there probably isn't a facilities manager in his right mind in a hospital, or any building for that matter, who wouldn't rather shut it down then suffer the consequense of a fault.
8,12,24 hours or so to pull the cable in and terminate is a small problem compared to the havic an outage would be.
15 years ago a world reknowned hospitalal in Boston suffered a fault. There primary feeders AND life safety feeders ran thru a common junction box in a STEAM room. Well the primary faulted and took the Life safety with it. 1/2 tha campus was in the dark.
I realise in todays codes this is not allowed and this situation is probably on the far end of the spectrum as to the consequences that would be endured if a coffee shop was closed for a couple days due to a failure. But the short of it is, as mentioned in many other posts, IT IS NOT WORTH THE RISK. If it can be shut down SHUT IT DOWN. then everyone can go home at the end of the day and see thier beautiful wives and children, which is why we work anyway, right. (Where would they be if we didn't come home from work because of something that could have been avoided)?
Remember, All accidents are avoidable. Prepare a proper Hazard Analysis before any task and you will decrease your injuries. Its proven.

Good Morning everyone!!!!!!! well I am just about to print off all the responses so far. Thanks to everyone!!! I now have some ammo to respond to the city's request to do this live.

This is easy. Get a temporary transformer to feed the building. No need to work the POCO transformer hot. The coffee shop will have to hire someone for temp portable power. Everyone will be happy. Coffee shop stays open,, men working near POCO trans is safe and job gets done.

Going by the posts of rck and harold.
And by my own experience, what's the point in working LIVE?.
bill woods, have you taken notice of what has been said about live work in the Occupational Safety Area?.
I work up to 66kV with Live Glove and Barrier work over here in New Zealand, underground and overhead.
If you can possibly avoid it, work dead, HV's have no friends and you only need make one mistake IMO.
Neoprene blankets or not, there is only so much that you can do.
Even if it is on the city's head, nothing can take away the pain and suffering of burns from a HV flashover.
Just remember that.

Ryan I am not as positive as you are on this.



I imagine you are referring to 1910.333(A)(1)?

One of the examples of an increased hazard allowing live work is simply removal of illumination for an area.


That said it's just a coffee shop, do it off hours, provide temp power or have a scheduled shutdown.

It always comes down to money, remember the people asking you to do this 'favor' are not taking the risk of a stay in the burn ward or worse.

The 'CITY' wants it done live - a COFFE SHOP...This sounds very political to me.

Most electricians are not properly trained to do this work. OSHA does say it can be live if removing power creates a hazard...Give me a break, I mean give those guys doing the work a break

I hope this contractor has a written procedure and documentation of the proper training or he may be in big do-do.

I agree with a generator temporarily feeding the coffee shop if they want to keep it open.

I SEE ABSOLUTELY NO GOOD REASON HERE TO KEEP THE POWER ON - SHOW ME ONE GOOD REASON!!!

Do it on an outage, maybe a monday night in the wee hours. Surely it can't take more than a few hours, and how many people want donuts and coffee at 1am monday morning?
I make a habit to not trust the government(city or otherwise) in any matters concerning my well being. They already take enough from us.
Don't give 'em your life.
Let us know how this turns out

I bet you will pi$$ off less people who can't buy coffee at 2 o'clock in the morning than the number of family members that will show up at the funeral.

Guys,
If I may put one final word in here.
As a person that is trained in HV line work, as soon as the authorities found out that people could work HV systems LIVE, there was a huge jump for everyone to be doing this, regardless of who they were and regardless of thier level of training.
Personally, I would leave a job like this to the PoCo, not because I work for one, but because they have the best idea of what is involved.
The biggest PITB now is the fact that all users of electricity have come to expect no "gaps" supply, that should change.
But don't get me started on that!. GRRR

We sure agree there, I have taken to just killing circuits without asking anymore.

Sure there are some areas (data centers, health care, labs etc.) where I will plan a scheduled shutdown.

However retail stores, apartments, condos, many office buildings etc. I do not ask anymore.

If you ask the answer is always the same...NO.

I just make the shutdown as short as possible.

If this is a pad mount doesn't it have a slabox? I know some don't but if it does the pull could be done without even getting into the transformer and having a short shutdown to terminate.
Anyway, if you do it live this is the kind of PPE you will have to wear.





[This message has been edited by Nick (edited 05-01-2005).]

500KW generator. It could run the better part of some neighborhoods, dont think a coffee shop would be a problem. And I'm sure you POCO has one laying around, possiblily larger. I have seen them parallel gensets to line and drop transformers for this type of thing before. Would be completely illegal for you to do it, but if this coffee shop has that kind of pull, I imagine they could get the POCO to jump a few hoops too. Hey, why not get them to pull and terminate at the tranny for you?

Good morning everyone. Well needless to say I have deciced to do this pull DEAD. I don't want anybody hurt. If there is a safer way to do something then do it that way!! I have no idea why the city expects us to do this live. As suggested it may be political or not. The coffee shop informed me that the baker starts at 2:00 am. We have tentatively scheduled the pull for 1:00am to 5:00 am. The last pull we did through a xfrmr the city told us that the primaries were not grounded. Will someone explain that to me. Should the primaries be grounded? We are not HV linesmen, just fantastic low voltage electricians! Thanks guys!!!!

the story ain't over yet!! contrary to the info in my previuos post the cable pull is going ahead this morning!!!!!

Last up-date on the cable pull through a live xfrmr. The boys got it done. No injuries!!!!! The company owner ran the tugger located a few yards from the xfrmr and pulled the cable into the xfrmr. I suggested he should wear a harness and tether so he could not reach the xfrmr. There were city linesmen present for the pull. I had an out of town sevice call to take care of. I did submit a letter to the company spelling out my concerns. I made it clear that I would not be participating in the pull. I am glad it is over. Man have I been stressing. This will NOT happen again. At least not on my watch.
Work safe boys!

Wouldn't the safest way to pull it, since you had to do it live, would have been to feed at the transformer?

The most danger is until the head is into the conduit. It should be taped up good. Then you should be able to feed from outside the transformer.

This would limit the danger since you have more control where the head is while you feed than when it come out.

I would have pushed to have a shut down during the night to do this pull. I am also the owner my company. I am the most valuable person in the company. If I got hurt during the pull, my guys would have no work too. Scheduled outages are a normal thing for construction with the POCO.



[This message has been edited by tkb (edited 05-03-2005).]

I don't think anyone asked this,

If you had to pull it live, you must have to connect it live.

What PPE will your owner use to make this connection, since it sounds like he didn't use any on the pull?

Just What I thought you was going to have to do (do it hot)I'm sure the POCO people assured your helper what the danger was and told him they were first aid trained, and i'll bet a $1 he was not even close to the 25kv it would of been behind a barrier and its door closed, and your low side voltage ??? you never said what it was 240 or 208 now if it was 480 it would be more a concern. now that the cable is in someone going to have to connect it, then connect 1st at you first OCPD go back to transformer read with megger or your simpson for and resistance/grounds and connect it, tape up your wrenches 1 or 2 wraps of good tape should be enough and where rubber gloves alonf with other PPE, face shield etc.
I spent my whole career in the electric utility field and am qaulified to work things hot. I got to admit I recall seeing many EC's coming into to do work for the POCO and just assazed of what goes on, oh dont get me wrong there times when it just has to be de-energized. and the POCO I worked for would of been doing the work that you just did, but do know of other POCO's (mostly city/town owned POCO's)that require the EC to do the work you just did. maybe you should consider yourself somewhat trained now and have a market for doing it now.