Messenger Cable

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nakulak

Senior Member
We are gogin to have a ground rod at every pole and run a ground down to it? Or possibly( doubt it) a separate ground wire run pole to pole.

sounds like it would be a good idea for you to buy mike's cd on grounding and bonding (not being sarcastic). where is the main ? If the main is at the first pole, or ahead of it, you need an egc and a neutral, in which case, as bob implied, the messenger is usually the egc. Putting a ground rod at each pole might make an engineeer feel good about lightning strikes to the pole, but you would have just as good an egc as if you stuck a monkey at each pole waving a ground rod. (egc = low impedance path to source) (of course, if the main is at the end of the poles then you can ignore everything I said)
 
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Alwayslearningelec

Senior Member
Location
NJ
Occupation
Estimator
With quadraplex you should have three insulated and one bare conductor. The insulated conductors should be the hots and the neutral and the bare would be the grounding conductor.

If you aren't doing it this way please explain.

See attached. This is a quadruplex but if it is 3 phase then their are 3 hots as shown and the bare...not 2...correct?

Thanks.
 

iwire

Moderator
Staff member
Location
Massachusetts
So are you are talking about four runs of 2 AL running from DPL-3 to the various loads?

You need to run an EGC.

I also really question the design of 2 AL on a 100 amp breaker.
 

Alwayslearningelec

Senior Member
Location
NJ
Occupation
Estimator
So are you are talking about four runs of 2 AL running from DPL-3 to the various loads?

You need to run an EGC.

I also really question the design of 2 AL on a 100 amp breaker.


Yes from DPL-1,2#3 to various loads. What are you questioning? Thanks.
 

mkgrady

Senior Member
Location
Massachusetts
I took a quick look at your one line. Some things occurred to me that might be worth bring up. I think you indicated in another thread that this is design build.

You are first converting the 4160 line to 480. I assume the 1000 KVA transformer is at the temp building you have described elsewhere. And then the 480 is distributed from the temp buildings 480 volt distribution switchgear to numerous loads that many appear to be seperate buildings. Seems to me you should consider running the 4160 throughout the area on a pole line. Whereever you need a service to a building you can hang a pole mount transformer to feed it and any nearby buildings. You can save alot of cable and labor that way and then you can forget about not having enough conductors in your quadraplex secondary cables. You could even skip the temp building, the 1000 KVA transformer and all the switchgear in it.

I get the feeling you are approaching this job like an inside electrical contractor when you should be thinking more like a power company.

I don't understand why you have insulation on your overhead 5KV cable. It needs to be insulated only where it is run underground.
 

Alwayslearningelec

Senior Member
Location
NJ
Occupation
Estimator
I took a quick look at your one line. Some things occurred to me that might be worth bring up. I think you indicated in another thread that this is design build.

You are first converting the 4160 line to 480. I assume the 1000 KVA transformer is at the temp building you have described elsewhere. And then the 480 is distributed from the temp buildings 480 volt distribution switchgear to numerous loads that many appear to be seperate buildings. Seems to me you should consider running the 4160 throughout the area on a pole line. Whereever you need a service to a building you can hang a pole mount transformer to feed it and any nearby buildings. You can save alot of cable and labor that way and then you can forget about not having enough conductors in your quadraplex secondary cables. You could even skip the temp building, the 1000 KVA transformer and all the switchgear in it.

I get the feeling you are approaching this job like an inside electrical contractor when you should be thinking more like a power company.

I don't understand why you have insulation on your overhead 5KV cable. It needs to be insulated only where it is run underground.

Thanks very much MK. I actually mentioned that to my engineer and he said maybe when we win the job but it we distribute 277/480 it will bring our costs down and that's how we win the job. So instead of stepping down and feeding from DPL-1,2&3 we should leave it as high voltage and step down near LPL-1,2,3,5 &6 and the other loads the DPL-3 are feedding correct? I am goging to tell him again tomorrow. It may be worth mentioning that the average run from the DPL panels to the loads is about 250' not too far. Thanks again. And about the 5KV it can be run bare????
 

mkgrady

Senior Member
Location
Massachusetts
Thanks very much MK. I actually mentioned that to my engineer and he said maybe when we win the job but it we distribute 277/480 it will bring our costs down and that's how we win the job. So instead of stepping down and feeding from DPL-1,2&3 we should leave it as high voltage and step down near LPL-1,2,3,5 &6 and the other loads the DPL-3 are feedding correct? I am goging to tell him again tomorrow. It may be worth mentioning that the average run from the DPL panels to the loads is about 250' not too far. Thanks again. And about the 5KV it can be run bare????

I'm saying your costs could be substantially less by running the primary to pole mount transformers where they are needed. From there you run triplex or quadraplex to your single phase or three phase loads. If you keep EVERYTHING overhead you will save alot of money.

Yes the 5KV can be run bare anywhere it is overhead. It is hardly ever done any other way. The typical exception would be Hendrix cable. Look up at most utility poles and you will find the primary run bare from pole to pole attached to insulators. Each phase (where more than one is required) is a couple of feet apart. Whereever a transformer to power a building is needed a bare wire is spliced on and run to the pole mount transformer thru a primary cutout fused switch.
 

Alwayslearningelec

Senior Member
Location
NJ
Occupation
Estimator
I'm saying your costs could be substantially less by running the primary to pole mount transformers where they are needed. From there you run triplex or quadraplex to your single phase or three phase loads. If you keep EVERYTHING overhead you will save alot of money.

Yes the 5KV can be run bare anywhere it is overhead. It is hardly ever done any other way. The typical exception would be Hendrix cable. Look up at most utility poles and you will find the primary run bare from pole to pole attached to insulators. Each phase (where more than one is required) is a couple of feet apart. Whereever a transformer to power a building is needed a bare wire is spliced on and run to the pole mount transformer thru a primary cutout fused switch.

LOL...I have been looking up a lot since I have been doing this job and actually I have seen all the cable and it looks all to be in a black jacket(insulation). I really have not noticed anything bare copper??

Also MK i really need you help with one thing, I have gotten some good feedback but want to make sure. How do you support quad/triplex cable from a wood pole? Hooks? Thanks VERY much.
 

roger

Moderator
Staff member
Location
Fl
Occupation
Retired Electrician
And about the 5KV it can be run bare????

Yes.

Horsegoer, if you do win this job, who is going to do the installation? Given the questions you have been asking over the last few weeks makes it apparent that your company is not experienced in this type of work.

A few things to consider, MV terminations, (if you don't have anyone familiar with making them), testing the cables and terminations after the installation, (do you have the equipment or are you going to use a sub-contractor) rigging for messenger type installations, this will probably involve more than one bucket and or line truck.

Roger
 

mkgrady

Senior Member
Location
Massachusetts
LOL...I have been looking up a lot since I have been doing this job and actually I have seen all the cable and it looks all to be in a black jacket(insulation). I really have not noticed anything bare copper??

Also MK i really need you help with one thing, I have gotten some good feedback but want to make sure. How do you support quad/triplex cable from a wood pole? Hooks? Thanks VERY much.

It is just a clamp on the end of a long bolt that runs through a hole drilled through the pole. I don't remember what it is called. They only cost a few bucks each.

You may want to get a couple of quotes from outside line contractors to do all the overhead work. If your workers have never done it I doubt the job will be successful.
 

Alwayslearningelec

Senior Member
Location
NJ
Occupation
Estimator
It is just a clamp on the end of a long bolt that runs through a hole drilled through the pole. I don't remember what it is called. They only cost a few bucks each.

You may want to get a couple of quotes from outside line contractors to do all the overhead work. If your workers have never done it I doubt the job will be successful.

Thanks so much MK. Yeah one of the other bidders is a company who does a lot of this "utility" type work? Have a feeling they know the ins/outs of this which will give them a huge advantage. Thanks again
 

kwired

Electron manager
Location
NE Nebraska
Thanks so much MK. Yeah one of the other bidders is a company who does a lot of this "utility" type work? Have a feeling they know the ins/outs of this which will give them a huge advantage. Thanks again

Not to mention there can be a lot of equipment needed to work on meduim voltage that is not needed for low voltage work, especially if there is to be any hot work. Working with these voltage levels is a slightly different breed of electrician as far as training than your typical electrician.
 
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