Wellhouse waterpipe

Status
Not open for further replies.
This may be the first time I've posted here- my question surrounds the proper connection of a municipal wellhouse water pipe to the grounding electrode system. I am more a troubleshooter than an installer, and I have been working lately in several municipal well water pump houses and haven't seen a "grounding electrode conductor" connected to any of the discharge piping. Generally, these wellhouses are 30 plus yrs old w/ varying degrees of mods thru the years. The supplies are 480 v 3 wire corner gnd delta to a control panel, supplying 50 hp submersible pumps. The piping within the wellhouse is usually 8 foot or so of 4-6 inch cast iron before it exits thru the wall, and steel piping all the way back to the pump. Usually there is a conduit run to the pump with a foot or so of sealtite on to the junction box. Am i missing something or should there be a GEC and clamp run to the piping. I about fell over when I saw the price of a 6 inch ground clamp- glorified U bolt w/ copper strap.
 

augie47

Moderator
Staff member
Location
Tennessee
Occupation
State Electrical Inspector (Retired)
250.52(A) lists a metal underground water system as a grounding electrode and 250.24 requires the electrodes be connected to the grounded service conductor.
Likewise 250.104 would require bonding if the metallic system was not underground.
In addition 250.52 requires the metal well casing to be bonded to the pipe.

In regard to the 6" clamp, what I normally see is that at some point there is smaller piping stubbed off to controls/faucet, etc. and the connection is made to this smaller pipe. You do have to keep in mind the "within 5 ft" rule in 250.52.
 

Dennis Alwon

Moderator
Staff member
Location
Chapel Hill, NC
Occupation
Retired Electrical Contractor
I assume there is a sub panel in the well house??? Generally we just run a feed to the pump house and the pressure switch etc is at the house. In this case the egc is all we use to bond the pipe since no electrode is necessary. If you need a gec can you just drill and tap the casing.
 

augie47

Moderator
Staff member
Location
Tennessee
Occupation
State Electrical Inspector (Retired)
An added noted... when I saw 50 HP I missed "submersible" as I did not know they existed. (shelterd life :grin:). Note 250.122(M) requires the pump EGC to be connected to the well housing.

Dennis, why woud a sub panel, if this were one, not require a grounding electrode ?
 

Dennis Alwon

Moderator
Staff member
Location
Chapel Hill, NC
Occupation
Retired Electrical Contractor
An added noted... when I saw 50 HP I missed "submersible" as I did not know they existed. (shelterd life :grin:). Note 250.122(M) requires the pump EGC to be connected to the well housing.

Dennis, why woud a sub panel, if this were one, not require a grounding electrode ?

Sorry- I didn't mean to imply that. I was trying to say that a panel would need a gec but a single circuit would not.
 
Thanks for the replies. In most of these cases, the panel with motor controller, start contact etc is the service panel. Power drop right to the breaker in the control panel. The reason why it dawned on me that I haven't noticed a connection at any of the piping is that in the panel I'm working now, the grounded supply conductor (480 corner ground) was not bonded to the panel anywhere, the 3 phases conductors landed right on the breaker. The only grounded connection at at panel at all was a ground rod. Actually I also noticed that the ground connection at the xformer had been compromised. Been this way for years, surprising that nobody ever got "bit". Power company jumped on that one pronto.
 
Also, I did remember about connecting to the pipe within 5 feet, but in this case, at least from a safety standpoint, would it really matter where the connection was made. On one end, the well piping goes down to the water strata (which could bunches o feet down) and the other end goes underground. At the well head there is a 2 inch vent pipe that could be used to clamp around, but at the other end (exiting the building, just the 6 inch pipe, nothing smaller to clamp too.
 

Dennis Alwon

Moderator
Staff member
Location
Chapel Hill, NC
Occupation
Retired Electrical Contractor
Also, I did remember about connecting to the pipe within 5 feet, but in this case, at least from a safety standpoint, would it really matter where the connection was made. On one end, the well piping goes down to the water strata (which could bunches o feet down) and the other end goes underground. At the well head there is a 2 inch vent pipe that could be used to clamp around, but at the other end (exiting the building, just the 6 inch pipe, nothing smaller to clamp too.

I think the reasoning for the 5' at the house is to hopefully keep the gec from being removed when plastic pipe gets installed in the system. Even the water softening systems, filters etc are plumbed with plastic.
 
Last response- someone made a comment about having never seen a submersible 50 hp motor- really these deep wells are pretty amazing. This particular well is 900 feet deep. The motor is at the bottom shaft up with the pump bolted on top. Then 20 foot lengths of well pipe connect the pump discharge to the surface. The only thing about screwed water pipe in any instance(well or otherwise) is the pipe dope that might be used on the threads. That always made me wonder how effective the grounding connection on threaded pipe really is?
 

Dennis Alwon

Moderator
Staff member
Location
Chapel Hill, NC
Occupation
Retired Electrical Contractor
Isn't there a well casing-- the water pipe is inside the casing so I still don't see why you can't just drill and tap the casing.
 
Location
NE (9.06 miles @5.9 Degrees from Winged Horses)
Occupation
EC - retired
Last response- someone made a comment about having never seen a submersible 50 hp motor- really these deep wells are pretty amazing. This particular well is 900 feet deep. The motor is at the bottom shaft up with the pump bolted on top. Then 20 foot lengths of well pipe connect the pump discharge to the surface. The only thing about screwed water pipe in any instance(well or otherwise) is the pipe dope that might be used on the threads. That always made me wonder how effective the grounding connection on threaded pipe really is?

The drop pipe does not meet the qualifications for a GE and while it may provide some path for current from a faulted pump that is not its intended purpose.
 
Status
Not open for further replies.
Top