Cathodic Protection Grounding

[Gategator37]

When a water line has cathodic protection joints, are we the electricians supposed to bond after the seperation "dielectric"? Or could water still be considered a current path back to the cathodic protection?

 

[Dennis Alwon]

When a water line has cathodic protection joints, are we the electricians supposed to bond after the seperation "dielectric"? Or could water still be considered a current path back to the cathodic protection?

Where is this dielectric joint. Water pipes need to be bonded whether or not there is a dielectric joint if the pipes are metallic. If the joint were in the building then I would jump to both sides of the fitting.

 

[richxtlc]

Where is this dielectric joint. Water pipes need to be bonded whether or not there is a dielectric joint if the pipes are metallic. If the joint were in the building then I would jump to both sides of the fitting.

The dielectric fitting is there for a reason. Bypassing it can create more problems then you solve. You need to know why there is an insulated joint at that location. You may be able to bond to the external side of the dielectric thereby maintaining ground to the system.

 

[zbang]

You may be able to bond to the external side of the dielectric thereby maintaining ground to the system.

Of course, if you're bonding the outside part and the interior system is metallic, they you need to bond it, too, thereby effectively jumpering the joint.

 

[Dennis Alwon]

The dielectric fitting is there for a reason. Bypassing it can create more problems then you solve. You need to know why there is an insulated joint at that location. You may be able to bond to the external side of the dielectric thereby maintaining ground to the system.

If the underground water pipe is metallic and in contact with the earth for 10' or more I am requiresd to bond that water line within 5' of where it enters the building. I also need to bond the water pipe on the load side of the fitting. If this line is for fire sprinklers then we have other issue but I don't see a way around it.

I was curious as to why there is a dielectric fitting on a water line-- I have not seen that except for on fire sprinklers.

 

[USMC1302]

Dennis:
In this area, you can typically find buildings with a variety of water piping materials. If there isn't a dielectric fitting between the copper and galvanized(common here) I'd bet on a leak with in a year.

 

[Dennis Alwon]

Dennis:
In this area, you can typically find buildings with a variety of water piping materials. If there isn't a dielectric fitting between the copper and galvanized(common here) I'd bet on a leak with in a year.

So is there a problem with jumping a GEC from one side to the other or is connecting to the street side not req.

 

[USMC1302]

Dennis:
Excellent question. Help me out here, as I look to this forum as a wealth of knowledge. I was making a general statement towards your question of why you might find a dielectric union in a water piping system. Those fittings can be anywhere in the system where dissimilar metal piping systems are joined. If you bond the water pipe upstream of this system, before the dielectric, you have done what you are supposed to do? What if the dielectric is buried 8' out from the house? Never really thought about it.

 

[USMC1302]

Dennis:
I did a quick search and found some other threads here about it. I agree with those that stated the appropriate bonding clamp on each side should be used if you have to jumper the fitting. I would still think some degradation will occur over time, but not as severe or quick as a direct connection between the pipes. I guess what I was trying to point out is just because we bond the water pipe in one location, doesn't guarantee how much of the piping system is electrically continuous.

 

[SG-1]

One reason for a dielectric union not yet mentioned in this thread is " objectionable current", specifically neutral current.

You should check for voltage before attempting to bond across the dielectric union & check for current before breaking a bond.