Feeder riser clamp

[NAZ55]

Is anyone aware of any non magnetice or non metallic feeder rised clamp to avoid any magnetic coupling and circulating current in the clamp itself?

If you do I will appreciate a quick response.

Thanks a lot in advance.

 

[EEJaime]

I am not sure what this "feeder riser clamp" might be. Are you talking about cable supports in a long vertical riser? Or something else? If it's the first, than I would suggest Kellums cord grips-there are many varieties. If you mean something else, more info is needed.

 

[Marmite]

These are commonly available. Where you source them would depend on where you are. A UK based Company is Ellis Patents

http://www.ellispatents.co.uk/Electrical/

Regards
Marmite

 

[EEJaime]

Marmite,
Those look effective, are they intended for verticle cable runs? The data does not specifically state so I was thinking something like this-

http://www.hubbellcatalog.com/wiring/catalogpages/section-t.pdf

Anyway, zazmat, hope this is what you are looking for.

 

[NAZ55]

To be more specific I need to clamp aluminum pipe about 3-4" containing two 15kV 2000kcmil shielded cables to the the riser pole. The concern is the circulating current in the clamp due to magnetic coupling.

 

[waross]

Unistrut and stainless steel clamps.
Look at M5060

http://www.unistrut.com/Browse/cat_detail.php?S=S06&P=M5025

Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[NAZ55]

I appreciate all your comments, but I need a clamp which can support a vertical run attaching conduit to the pole.

Bill,

It appears that the one you sent is for horizontal run and attaches to the unistrut

 

[waross]

Mount the unistrut horizontally with the opening facing forward. Run the conduit vertically. Install the clamp. These clamps are used in any position.
Also check out the P2054.

http://www.unistrut.com/Browse/cat_detail.php?S=S06&P=P2024

I understand that these are available in stainless.

Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[NAZ55]

I am not sure how this would get rid of the circulating current?

 

[patrick7961]

yes they are abailable, I was in a substation which used some type of composite material not sure what it was tho.
kinda like a plastic/fiberglass mix. I do not know where they got them from. I know that did not help.
however you can just continue to use the metal ones by removing the standard metal bolt and useing a fiber/plastic bolt (path broken) should be able to get these at a bolt supplyer.

 

[waross]

Use the stainless steel option. With no induced magnetism, the heating of the clamp is negligible. A few years ago we installed a substation with 750 mcm single conductor cables.
The PVC conduits were strapped with stainless type "P" straps. This was the utility standard.
Yes, one cable per conduit.

Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[busbar]

 
I was certain

http://www.alumaform.com

had a riser product in common use by electric utilities that would fit your application but I can’t seem to find it online.

 

[waross]

Go to

http://www.alumaform.com/equipment_mount.pdf

and scroll down to "conduit Standoff Brackets"
We used the unistrut at one end of the 5" PVC conduits and the Aluma-Form brackets at the pole end.
Thanks for the lead, busbar.

Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[busbar]

Thanks for the pointer, waross. With aluminum channel to break the “magnetic loop/circuit”, ordinary plated-steel conduit clamps could be used in place of non-ferrous material.

 

[waross]

I agree, busbar.

Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[ScottyUK]

I'll second Marmite's suggestion. We have used the Emperor range on a few jobs; they are well made and easy to install according to feedback from the cable crew, and worth the slight cost premium over some other suppliers. Installation was to ladder rack in horizontal and vertical orientation.


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If we learn from our mistakes I'm getting a great education!

 

[resqcapt19]

I am just an electrician and this really beyond my scope of knowledge, but it is my understanding that is only an issue when you do not have all three phases within the same magnetic clamp. Is my understanding incorrect?

 

[waross]

resqcapt19;
It's sometimes called magnetic encirclement. Below about 200 amps it is not much of an issue. Above 200 amps things start to get hot. All three phases (plus neutral if used) should go through the same opening in a magnetic material. This may be a clamp, a conduit or a hole into a panel. The magnetic encirclement may be broken by using a nonmagnetic bolt on a two piece strut clamp if the two magnetic sides of the clamp do not touch.
If single conductor cables enter a panel through separate holes, the holes may be joined by a hacksaw cut. Now you have one oddly shaped hole, but it will avoid the heating.

Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[resqcapt19]

Bill,
Thanks. I understand the issue with single conductors and ferrous materials that encircle the conductor. I assumed that in this case we do have all of the circuit conductors within a single cable, and if that is the case, I still don't understand. That would be a very common field installation.
Don

 

[NAZ55]

resq, regarding your initial post,that is correct, all phases are mounted separately. This is because of the size of the cable and conduit per phase. i.e two 15kV 2000kcmil cables in 4" conduit per phase.