Help with Overhead Temp

[iwire]

In a few days I have to do some work I am not familiar with.

I have to run a Temp 480 Volt 200 Amp (no neutral) feed between two wood poles (typical telephone poles).


1) What is the name of the wedge like clamp that grabs the messenger cable and who makes them?

2) What is the name of the cable is it called triplex? I need 3 hots and messenger/ground.

3) What ampacity table would I use for this?

Any help would be appreciated

Bob

 

[russellroberts]

Re: Help with Overhead Temp

Iwire,the clamp I think is called a deadman.At least thats what the poco guys here call them.If I need one I have some good friends at the poco that get them for me.I've never asked for one at the supplier. russell

 

[paul]

Re: Help with Overhead Temp

1) What is the name of the wedge like clamp that grabs the messenger cable and who makes them?

Messenger Clamp.

2) What is the name of the cable is it called triplex? I need 3 hots and messenger/ground.

Yes, triplex. However, make sure you specify you need three conductors on it.

3) What ampacity table would I use for this?

Table 310.17

[ February 24, 2003, 07:14 PM: Message edited by: paul ]

 

[cm]

Re: Help with Overhead Temp

I WIRE [1]The clamp is called a wedgegrip and is also known as a sling,you could also use a preformed wire grip,I am not positive but porcelin products or black burn makes it. [2]1 insulated and 1 bare is called duplex,2 insulated and 1 bare is called triplex,3insulated and 1 bare is called quadraplex. [3] I dont know that I would use the free air chart you need to take voltage drop and load into consideration the last time I did this it was to replace a lateral under a medical arts building building so they could build an addition we kept it full size. also if you use 4/0 triplex you need to watch the span its heavy and sags a lot and I would recomend useing long poles and bolted clevices not 1 point insulators hope this helps

[ February 24, 2003, 07:32 PM: Message edited by: cm ]

 

[luke warmwater]

Re: Help with Overhead Temp

Bob, I've heard all of the others, we typically refer to them as Wedge Clamps. For your installation you may want to go with the 2-bolt type made by Fargo. As cm points out the span(typically 150-200ft.) is going to be heavy. I wouldn't use pre-forms. They are mainly for single wire Al high voltage lines or guy wires. Post back if you need to know how to get this up with minimal sag. Definately attach to eyebolts(drill through pole and use a square washer and 5/8 nut) and not to screw-in porcelains. Or use porcelain with off-set eye through pole. Are you installing poles or are they existing? Todd

 

[paul]

Re: Help with Overhead Temp

CM,

Why would you not use the free air chart? It's outside in free air. Just wondering...

Personally, I would go with the AL and not CU. It's lighter and easier to string up. I also agree about using the eye-bolt through the pole. It's a much stronger installation. I, too have heard all the terms. I was taught the term 'messenger clamp' originally. I do belied it is black burns. For some reason that rings a bell to me.

Goodluck

 

[charlie]

Re: Help with Overhead Temp

We use a 5/8" through bolt with an eye nut on the end or a 5/8" eye bolt that goes through the pole. For 200 amperes, we use #2 Al. Quad. and have no problems with it burning down, then we use service grips (preformed grips to hold the neutral [messenger]). We also use compression connectors that are pressed on. The inspectors here will allow that to be used for a temporary installation since it is outside and not permanent. Additionally, you will have no problem with the grips holding a long span unless you pull it in like a banjo.

Note, #2 Al. quad. will not meet Code. If the AHJ enforces the Code, you will probably have to use 2/0 or 4/0 AL. (depends on what the supply house has on hand).

Don't forget about guying the span! Assuming (there's that word again) the span is pulled up fairly tight; the poles could be over stressed. Additionally, make sure the poles are strong enough for the transverse loading incurred. Normally, you will need class 5 poles.

 

[iwire]

Re: Help with Overhead Temp

Thank you all for the great info, the job is done. I ended up using 4/0 AL for the length, I was adding to existing (that was a long run of 2/0 AL) I ended up using the heavy 5/8" hardware left from some poles that had been removed and left on the ground.

The poles where existing and "guyed" I do not know what class.

Thanks again Bob