bonding rigid conduit riser

[gserve]

I have a utility requiring me to"ground" the rigid conduit used as a riser up a telephone pole for protection of the service lateral conductors. This riser uses a rigid steel 90 degree sweep attached to the riser. Question: How do I bond this? Drive a ground rod and attach a bolt on lug to the conduit??? Any ideas out there? All suggestions and ideas please. This is in Maine CMP. Any Mainers out there? NOTE: They also want PVC conduit from the top of the rigid to go all the way up the pole. So a bonding bushing is out.

 

[bennie]

Re: bonding rigid conduit riser

Ask the utility. Can the 90 be changed to PVC?

 

[gserve]

Re: bonding rigid conduit riser

Bernie,Even if it could I would still have to ground the rigid(PVC on both ends)

 

[bennie]

Re: bonding rigid conduit riser

I don't understand what you need to ground.

[ April 17, 2003, 07:53 PM: Message edited by: bennie ]

 

[bphgravity]

Re: bonding rigid conduit riser

What are you going to "ground" it to? Driving a ground rod isn't going to assist in clearing a conductor to conduit fault. Besides, if the riser is coming up from the ground and is attached to a metal elbow underground, it already is grounded, or at least in contact with Earth.

 

[gserve]

Re: bonding rigid conduit riser

I know it is already grounded but the utility will not hook up power unless I ground it. I'm looking for ways to physically do this. Any ideas?

 

[bphgravity]

Re: bonding rigid conduit riser

You can use a bolted ground strap. This product is similar to a hose clamp, but is listed for bonding and has a lug for a grounding conductor. See this link for an example: http://www.altfabrication.com/products/guide/viewgroup.aspx?productgroup=LP-C2BS

I have used these for lightning protection systems and they work very well.

[ April 17, 2003, 07:54 PM: Message edited by: bphgravity ]

 

[gserve]

Re: bonding rigid conduit riser

Thanks I checked out the link. Are these listed to bond conduit per NEC?

 

[vixcel]

Re: bonding rigid conduit riser

Try cadwelding a grounding jumper to the pipe. Ask the utility if you can bond to there ground at the bottom of the pole. Be carefull with the amount of charge you use with the cadweld, it can burn right thru the pipe.

 

[russ]

Re: bonding rigid conduit riser

This is a defect I have writen several contractors.
They will leave the meter under ground, once under ground they will switch to nonmetalic conduit. When they get to the utility pole they will switch back to ridgid conduit to come out of the ground and go up the pole. That leaves this conduit ungrounded.
My solution is to have the contractor install a ground conductor with the service wire. bond the ground wire in the meter or main. On the pole side I have them bring the ground out of the weather head and bond it to the conduit with a ground clamp.

Russ

 

[wirestu]

Re: bonding rigid conduit riser

Russ,

What kind of fitting do you require at the pole? I assume it is not a bond bushing since there is a weatherhead? Please provide a link to manufacturers web site.

Thanks

 

[russ]

Re: bonding rigid conduit riser

These are all water pipe clamps, and I allow them to be clamped on the riser conduit.

Some of these links have to be searched to find the clamps but all these companys have them.

Russ

Ilsco
http://www.ilsco.com/

Thomas + Betts THIS ONES NO GOOD
http://eleccat.tnb.com/tnbcat/tnbcat/webcat_search_results_dsp2.build_category_home_page?p_catalog_code=CKY&p_category_hier_id=CKY171

Erico
http://www.erico.com/erico_public/general_info/waterclamps.asp

[ April 22, 2003, 08:00 PM: Message edited by: russ ]

 

[luke warmwater]

Re: bonding rigid conduit riser

NEC permits you to use rigid 90's between the PVC underground: 250.86 Exception #3, as long as it is covered at least 18".
Do they Require a rigid riser??
If not, switch to a PVC riser, and use U-Guard.
If so, then bond it up top with a clamp.
Now, what size bond are you going to use?

 

[gwz2]

Re: bonding rigid conduit riser

Service Laterals ?

How do you work with the Poco when they install conductors to the meter ( 400 Amp and less ) and the electrical contractor installs the bonding jumper in the same lateral to bond the RMC 90? at the Poco pole ?

Locally, if the Laterals are over 400 Amps, the electrical contractor installs the conductors and installing a BJ for the RMC 90? 's would not be a problem. But, when 400 Amp or less then it becomes a problem.

 

[russ]

Re: bonding rigid conduit riser

Looks like we have a little difference in what the power companys will and wont do.

By me if the power company installs the lateral it's beyond my jurisdiction, they usually cover their wire going down the pole with a plastic wrap.
If a contractor installs it it has to be in rigid steel above ground, the Chicago code I use doesn't allow it to be in plastic above ground.

Russ