Common practice for well casings?

[TimWA]

Do you guys usually bond well casings with whatever equipment ground you run out there? I don't think there's an actual code reference for this- AHJ? I've been looping the equipment ground (#10 or #12 CU solid from the UF cable) out of a drilled hole in the PVC LB and drill/tap a lay-in lug in the well casing for it. I saw someone actually run a dedicated #4 out there just for the well casing (in addition to the equipment ground), I thought, you must be joking.

 

[Twoskinsoneman]

I guess it would be needed if you have metal water pipe from the well to the house.

250.52(A)(1) Metal Underground Water Pipe. A metal underground
water pipe in direct contact with the earth for 3.0 m (10 ft) or
more (including any metal well casing bonded to the pipe) and
electrically continuous (or made electrically continuous by
bonding around insulating joints or insulating pipe) to the
points of connection of the grounding electrode conductor and
the bonding conductor(s) or jumper(s), if installed.

 

[shortcircuit2]

Metal well casings MUST be bonded to the equipment grounding conductor from the branch ciruit that powers the pump. Find it in the NEC under 250.112(M)

This is so important and people have been electrocuted from an ungrounded well casing. Please bond your customers well casing and also next time your at a customers home with a well, just check to see if the well is bonded. You could save a life.

 

[shortcircuit2]

Here is a link to a sad story from last summer...

http://articles.kwch.com/2011-06-13/electrocuted_29655176

It has to be common practice to bond the well.

 

[Dennis Alwon]

The equipment grounding conductor is used to bond the well casing (250.112(M) as stated. The well casing is an electrode-- 250.52(A)(8)

 

[iwire]

The well casing is an electrode-- 250.52(A)(8)

A metal well casing can be used as an electrode but does not have to be.

250.50 Grounding Electrode System. All grounding electrodes
as described in 250.52(A)(1) through (A)(7) that are
present at each building or structure served shall be bonded
together to form the grounding electrode system. Where
none of these grounding electrodes exist, one or more of
the grounding electrodes specified in 250.52(A)(4) through
(A)(8) shall be installed and used.

Exception: Concrete-encased electrodes of existing buildings
or structures shall not be required to be part of the grounding
electrode system where the steel reinforcing bars or rods are
not accessible for use without disturbing the concrete.

 

[Dennis Alwon]

A metal well casing can be used as an electrode but does not have to be.

It is an electrode I didn't say it had to be brought back to the house. I stated the EGC can be used.

 

[gndrod]

casing-GEC & submersible Pump EGC

casing-GEC & submersible Pump EGC

Do you guys usually bond well casings with whatever equipment ground you run out there? I don't think there's an actual code reference for this- AHJ? I've been looping the equipment ground (#10 or #12 CU solid from the UF cable) out of a drilled hole in the PVC LB and drill/tap a lay-in lug in the well casing for it. I saw someone actually run a dedicated #4 out there just for the well casing (in addition to the equipment ground), I thought, you must be joking.

They were not joking if the pump size was for large agriculture or commercial installs. I see some really good responses in this thread that are spot on. Domestic well systems with PVC casings are more common in urban installations. In upgrading old deep submersibles that are metal cased and include other electrical BC disconnects...require all metal bonding.

Common installs for resi remote wellhead deep sub wells usually include a 3-wire 230 V motor with the EGC regardless of the direct buried water supply pipe and well seal being all PVC. Most steel captive storage tanks are located at the served structure and are bonded through the pressure switch manifold assembly EGC that continues in the direct burial UF cabling to the remote well head pump.

Even with a four wire system, a ground electrode system bonded to metal surrounding equipment at this point is used in a lightning prone environment.

 

[infinity]

A metal well casing can be used as an electrode but does not have to be.

As Bob stated it can be used as an electrode is not required to be used as one the electrodes that are present. That might explain why the #4 was run that was mentioned in the OP. My guess is that it would be one of the best electrodes.

 

[gndrod]

NEC Double talk...

NEC Double talk...

A metal well casing can be used as an electrode but does not have to be.

Maybe an NEC [250.50] tie-in with an IN reference is needed to make sure the metal well casing must have an EGC bond so as not to mislead that a well case electrode does not have to be bonded.

 

[WIMaster]

As Bob stated it can be used as an electrode is not required to be used as one the electrodes that are present. That might explain why the #4 was run that was mentioned in the OP. My guess is that it would be one of the best electrodes.

I do firmly believe a 6"-8" metal pipe going 30-450' in the ground is the best SINGLE ground rod I have ever seen at a single family dwelling to date. That is why whenever it is practical to do so or the customer wants a first rate job I run a full size grounding electrode conductor to the metal well casing. Not required but a first rate install IMO. Not always practical though, still gotta pay the bills.

 

[realolman]

seems to me if you're gonna run something out there it would have to be at least a # 6 because it seems to me it would be an GEC.

If you're not using it for a grounding electrode. I don't see the point in bonding it.

A # 10 or 12 as an EGC corresponding to the pump OCPD wouldn't be big enough, would it?

 

[Cow]

Our inspector won't let us use regular aluminum set screw lugs for this, we have to use the direct burial rated type. Anything outside, in his eyes, requires DB rated whether it's touching dirt or not.

 

[George Stolz]

seems to me if you're gonna run something out there it would have to be at least a # 6 because it seems to me it would be an GEC.

If you're not using it for a grounding electrode. I don't see the point in bonding it.

I think the odds of someone touching the well casing are a little higher than the service getting struck by lightning, don't you? :?

Bonding is far more important than using it as a grounding electrode.

 

[realolman]

I think the odds of someone touching the well casing are a little higher than the service getting struck by lightning, don't you? :?

I agree. but I don't know what that means.

Bonding is far more important than using it as a grounding electrode.

Please explain. I don't understand.

I don't know, but it seems to me that the well casing would be the primary grounding electrode and any ground rod would be supplemental, requiring at least a #6 to the well .... if the well casing would be connected to metallic waterpipe more than 10 ft long would require a GEC sized according to table 250.66.

 

[tom baker]

the wells I wire are 6" and up casing. I will have a 3/8" bolt welded to the casing and attached the EGC to it. the j box is normally on the well casing under the top plate. Newer drop cable has a EGC and it all gets tied together in the j box. If the well casing is close to the service I will use it as a part of the grounding electrode system.

 

[gndrod]

Experience

Experience

I agree. but I don't know what that means.




Please explain. I don't understand.

I don't know, but it seems to me that the well casing would be the primary grounding electrode and any ground rod would be supplemental, requiring at least a #6 to the well .... if the well casing would be connected to metallic waterpipe more than 10 ft long would require a GEC sized according to table 250.66.

Unless you do this for a living and have good reason to deviate from an EGC, the questions asked are understandable. In some instances the well casing, under code within a structure would require a grounding electrode.

In the instance of discussing a rural domestic water well system, the primary function of a metal well casing must be bonded as an Equipment Grounding device. The case EGC bonding prevents any ungrounded shorting to the casing causing a continuous energized and fatal potential that does not trip the well motor feed OCPD. An non-grounded Ground Electrode will not protect equipment from the case fault condition. A PVC casing and well polytube does have an advantage in this instance.

Secondarily, you may consider the metal casing a Ground Electrode for lightning dissipation should surrounding equipment be protected from being a lightning beacon...do not expect guarantees on this aspect.

On a practicality note, using a metal casing is no longer common for modern well installs for both handling, water purity and electrolysis reasons that this discussion does not entail. There are probably special conditions that may exist such as geothermal environs that may require metal casings, but that is another subject.

 

[Dennis Alwon]

The well casing may be an electrode but around here the well is often 100+ feet from the home. Does the gec being run that distance change the effectiveness of the electrode itself?

 

[iwire]

The well casing may be an electrode but around here the well is often 100+ feet from the home. Does the gec being run that distance change the effectiveness of the electrode itself?

I was going to bring that up.

I believe BPHGravity has pointed out that at the frequency lightning operates at that a typical copper conductor adds a lot of impedance.

I believe he also pointed out that only the first couple of feet of a grounding rod is effective for lightning.

 

[Dennis Alwon]

I was going to bring that up.

I believe BPHGravity has pointed out that at the frequency lightning operates at that a typical copper conductor adds a lot of impedance.

I believe he also pointed out that only the first couple of feet of a grounding rod is effective for lightning.

Is that true for ground rings and cee? If this is true I think it changes my view of life in general. :lol: