Just recently installed an air cooled generator and had it inspected. The 3/4" conduit from the residence to the generator goes underground. I used schedule 80 conduit at each end where it comes out of the ground. The Inspector said I needed to protect the conduit riser at the generator end from lawnmower/trimmer damage. I thought that installing schedule 80 conduit was the protection. I plan on calling the Inspector to talk about it but just wanted other's opinions. If you had to protect the conduit, what would you do? I thought about sliding a section of 1 1/2" conduit over the existing conduit and let it stick out above ground about 8 inches. Thanks to all who reply.:?
Conduit protection?
- Thread starter RESI
- Start date
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- Location
- Massachusetts
You are right, the NEC considers schedule 80 to be suitable for use in areas subject to damage.
- Location
- Chapel Hill, NC
- Occupation
- Retired Electrical Contractor
I agree with both of you.
Here is what I found on a pvc manufacturers site. The regular PVC is just called Heavy Wall.
Here is what I found on a pvc manufacturers site. The regular PVC is just called Heavy Wall.
PVC Rigid Nonmetallic Conduit (Extra Heavy Wall EPC-80) Listed for use in aboveground and belowground applications including areas subject to physical damage. Rated for use with 90?C conductors Superior weathering characteristics Identified for use in areas subject to physical damage in accordance to 352.12(C) 494* Series 1/2” – 6 ” Standard Radius and Special Radius Elbows available.
- Location
- Illinois
- Occupation
- retired electrician
Maybe the inspector considers that area to be subject to severe physical damage.
Strathead
Senior Member
- Location
- Ocala, Florida, USA
- Occupation
- Electrician/Estimator/Project Manager/Superintendent
Not that this dictates fact, but Schedule 80 PVC is used throughout the country down a power pole to feed utility transformers underground. The generally carries 12KV cabling. And your inspector wants to deem a generator feed inadequately protected?
petersonra
Senior Member
- Location
- Northern illinois
- Occupation
- engineer
I am inclined to agree that over time weed whacker damage will become apparent. Whether the code requires additional protection is something else. Some kind of sleeve is probably easiest, and will cost less than fighting over it.
renosteinke
Senior Member
- Location
- NE Arkansas
I'm inclined to say "humor the inspector."
Ultimately, it's a judgement call whether an installation is adequately protected. For example, I've seen a lovely EMT installation completely trashed by repeated impacts from pallet jack / stock picker / forklift traffic. In that instance, IMO, it would have been reasonable for the AHJ to require the conduit to be moved, or better protected.
Your inspector has looked at your instal, and has forseen a particular, very predictable hazard from ordinary maintenance.
Since the pipe is already in place, it's probably easiest to 'sleeve' the most exposed sides with a bit of strut.
Ultimately, it's a judgement call whether an installation is adequately protected. For example, I've seen a lovely EMT installation completely trashed by repeated impacts from pallet jack / stock picker / forklift traffic. In that instance, IMO, it would have been reasonable for the AHJ to require the conduit to be moved, or better protected.
Your inspector has looked at your instal, and has forseen a particular, very predictable hazard from ordinary maintenance.
Since the pipe is already in place, it's probably easiest to 'sleeve' the most exposed sides with a bit of strut.
kwired
Electron manager
- Location
- NE Nebraska
I'm sorry but this is worth a fight with said inspector. He needs to know he is not God.
What is the chance that same installation has the main service lateral just a few feet away in a Schedule 80 PVC and he has nothing to say about that?
Even RMC can be physically damaged although it takes more abuse to get it done.
One needs to know what abuse is likely when determining what physical protection is needed - but you never really know what will really happen. What if this install is facing the street and an out of control motorist hits it? There is something likely to damage it if it happens, but is not necessarily that likely to happen, not to mention there is likely damage to more than just this raceway if that happens.
What is the chance that same installation has the main service lateral just a few feet away in a Schedule 80 PVC and he has nothing to say about that?
Even RMC can be physically damaged although it takes more abuse to get it done.
One needs to know what abuse is likely when determining what physical protection is needed - but you never really know what will really happen. What if this install is facing the street and an out of control motorist hits it? There is something likely to damage it if it happens, but is not necessarily that likely to happen, not to mention there is likely damage to more than just this raceway if that happens.
petersonra
Senior Member
- Location
- Northern illinois
- Occupation
- engineer
If there is grass planted where the PVC pipe comes up thru the ground, it will almost certainly sustain damage from both lawn mowing and weed whacking. It is not just likely, it is all but certain.
The question is whether the damage that will be incurred merits additional protection.
I am never a fan of giving in to the bureaucrats when they are just being power mad control freaks
but this seems to me to be a legitimate concern.
kwired
Electron manager
- Location
- NE Nebraska
If there is grass planted where the PVC pipe comes up thru the ground, it will almost certainly sustain damage from both lawn mowing and weed whacking. It is not just likely, it is all but certain.
The question is whether the damage that will be incurred merits additional protection.
I am never a fan of giving in to the bureaucrats when they are just being power mad control freaks
There are millions of schedule 80 risers out of the ground subject to lawn mowers and weed whackers. I'm willing to bet only a very small percentage are ever damaged and it is likely that somewhat unusual situations have occured when they are damaged.
Brush blade on the trimmer instead of using typical nylon line would cause damage. It would also cause some damage on RMC although one incident like that would likely just result in a scratch.
petersonra
Senior Member
- Location
- Northern illinois
- Occupation
- engineer
I would bet it is closer to all of them get damaged. The question would be whether the level of damage makes additional protection necessary. Even just a nylon string trimmers will damage PVC. Whether it does more than just mark it up or not is another discussion.
rcarroll
Senior Member
- Location
- Fort Collins, Colorado
Good point! Years ago the state inspector had us install the pvc with the marking out to verify Sched 80
kwired
Electron manager
- Location
- NE Nebraska
I'm sure it can. Just how long do you suppose it takes to damage enough to compromise the integrity of the raceway.
If you sleeve the raceway with a larger piece of PVC you only get twice the lifetime of physical protection because it will damage the sleeve then racway and now it needs repaired. Guess we need to use RMC or encase it in concrete, or better yet encase RMC in concrete, wait, concrete is subject to damage by jackhammers:lol:
K8MHZ
Senior Member
- Occupation
- Electrician
kwired
Electron manager
- Location
- NE Nebraska
Did not read that whole thread but the best way to protect that from a snow plow would be with some bollards. Even RMC may be damaged by the snow plow. Worse than damaging the raceway is if the plow would happen to pull on a conductor and destroy the equipment the conductor was connected to.
Had a helper a few years ago. We just finished pulling some underground supply conductors to a panel at a site for grain storage bins. His next task was to trench another line that happened to come close to the line we just pulled. He knew it was there, and that he was to run the trencher shallow and hand dig the rest of way to existing line yet he managed to hit the line. Not only did it break the raceway it pulled a conductor which pulled on the main breaker, broke the main and tried to pull part of the main through the raceway. My patience was not very good that day, I ended up just telling him he had to fix it and tried to stay away from him as much as possible until it was done, which was probably a smart thing.
Strathead
Senior Member
- Location
- Ocala, Florida, USA
- Occupation
- Electrician/Estimator/Project Manager/Superintendent
As I stated earlier, schedule 80 riser is a typical installation for 12KV transformer primaries. Should we go through the Country changing all of them out?
elohr46
Senior Member
- Location
- square one
I've been weedwacking against my underground PVC service conduit for 37 years now, still not damaged. Ruined about 8 weedwackers though.
kwired
Electron manager
- Location
- NE Nebraska
You must not be buying the right weed whackers:happyyes:
renosteinke
Senior Member
- Location
- NE Arkansas
I think the question we're really asking is: Who gets to decide what protection is needed?
One approach is to assign the duty to some outside, uninvolved, expert, and let him make the call. That's what the inspector is doing. That's what many folks assert is right and proper every time we have a new code cycle.
Another approach, the more traditionally "American" approach, is to let the FREE citizen decide - and rely upon the market to help him.
"Lawn mower damage" is a very good example to use to illustrate this point. I've some rather flimsy solar lights simply stuck in the ground along my walkway .... and I've managed to not damage them at all in the past year.
By way of contrast, the nearby apartment complex has steel light poles that are leaning, or bent, or otherwise show damage, all from the activities of the grounds crew. It is almost as if these guys make it their mission to break things.
The usual response in that second situation is to keep patching things - until they get tired of 'minimal' stuff being broken, and take it upon themselves to beef things up.
There are just too many variables, too many judgement calls, for this situation to have a single answer. The OP needs to consider that the inspector just might have a better grasp of reality than he does .... and the inspector needs to know the difference between 'good design' and 'good law.'
One approach is to assign the duty to some outside, uninvolved, expert, and let him make the call. That's what the inspector is doing. That's what many folks assert is right and proper every time we have a new code cycle.
Another approach, the more traditionally "American" approach, is to let the FREE citizen decide - and rely upon the market to help him.
"Lawn mower damage" is a very good example to use to illustrate this point. I've some rather flimsy solar lights simply stuck in the ground along my walkway .... and I've managed to not damage them at all in the past year.
By way of contrast, the nearby apartment complex has steel light poles that are leaning, or bent, or otherwise show damage, all from the activities of the grounds crew. It is almost as if these guys make it their mission to break things.
The usual response in that second situation is to keep patching things - until they get tired of 'minimal' stuff being broken, and take it upon themselves to beef things up.
There are just too many variables, too many judgement calls, for this situation to have a single answer. The OP needs to consider that the inspector just might have a better grasp of reality than he does .... and the inspector needs to know the difference between 'good design' and 'good law.'
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