Trenching - multiple utilities

[4x4dually]

I still don't see what the issue with the "same trench" is. We had a job where due to utility requirements we needed three foot of separation from gas and other utilities. They dug a 6 ft wide trench and we put one on each side and one in the middle. All in the same trench.

I would venture to guess that when folks say "trench" they typically envision something that is 6-12" wide as a trencher would give. I doubt many think of something 6 ft wide. I'd have no issue with everything being in one wide trench. I was mostly envisioning all three utilities stacked on top of each other with the only one that might need maintenance on the bottom.

 

[jaggedben]

Adequate ??? Not hardly. Contrary to popular belief I'm an electrician, not a plumber or excavator. I don't have a copy of the 2021 NSPC 10.6 and 13.1.3 and the 2021 IFGC/IRC 404.12/G2415.12 handy. Why can't he just answer the SIMPLE questions I posed ?

2021 NSPC online right here dude. It's free.

2021 NSPC

epubs.iapmo.org

2018 IFGC https://up.codes/viewer/new_jersey/ifgc-2018
Okay he said 2021 but hopefully the relevant section hasn't changed.

Why am I doing this for you? It took 2 minutes with google.

I'm just trying to do the RIGHT job the FIRST time. As I've said before, many construction officials don't seem to want to tell you if you ARE doing the right job, but they CERTAINLY will tell you if you've done it WRONG and will cite the Code section(s).

Why do you think it's the inspector's job to tell you the code instead of your job as a contractor to be able to look it up? Between the code I know by heart and the stuff I know how look up I know way more of the code that's relevant to my work than almost every inspector. On the rare occasions that a mistake or a borderline interpretation happens in my work, the inspector usually doesn't notice.

 

[wwhitney]

Why am I doing this for you? It took 2 minutes with google.

Plus I already did it in post #9. : - )

Cheers, Wayne

 

[GeorgeB]

Wow! 54”…
Around here it’s 12”.

That's a nice thing about the southeastern coast.

 

[Knuckle Dragger]

There not in the same trench anymore once it's filled in.

 

[jaggedben]

I would venture to guess that when folks say "trench" they typically envision something that is 6-12" wide as a trencher would give. I doubt many think of something 6 ft wide. I'd have no issue with everything being in one wide trench. I was mostly envisioning all three utilities stacked on top of each other with the only one that might need maintenance on the bottom.

Still, the point is that what matters is the underground separations desired or required when everything is backfilled. Talking about a number of trenches instead of a required separation distances is just not a direct or useful way to discuss the subject. Tell the trench digger the requirements and let them decide how to dig it.

 

[wwhitney]

On the other hand, 300.3(B) does refer to conductors of a circuit being in the "same . . . trench," so apparently it is necessary to make a judgement as to what a trench is.

Does that mean that if I dig a single 48" wide trench and throw direct bury single conductor cables into it spread across the width, that's fine, while if I dig two 12" trenches separated by 24", and spread the conductors between the two trenches, it's not? : - )

Cheers, Wayne

 

[electrofelon]

On the other hand, 300.3(B) does refer to conductors of a circuit being in the "same . . . trench," so apparently it is necessary to make a judgement as to what a trench is.

Does that mean that if I dig a single 48" wide trench and throw direct bury single conductor cables into it spread across the width, that's fine, while if I dig two 12" trenches separated by 24", and spread the conductors between the two trenches, it's not? : - )

Cheers, Wayne

We are getting into that in this other thread

Neutral size for parallel underground service lateral

We have six parallel runs of 750MCM aluminum USE conductors per phase, going between the utility transformer and an open bottom 2000A outdoor service disconnect. My question is, how many neutrals (grounded conductors) do I need to run in that trench? Using the 12 1/2% rule from table...

forums.mikeholt.com

I say it says what it says. If anyone doesn't like it, they are welcome to submit a p i for this to be more specific and perhaps give distances.

 

[goldstar]

2021 NSPC online right here dude. It's free.

2021 NSPC

epubs.iapmo.org

2018 IFGC https://up.codes/viewer/new_jersey/ifgc-2018
Okay he said 2021 but hopefully the relevant section hasn't changed.

Why am I doing this for you? It took 2 minutes with google.


Why do you think it's the inspector's job to tell you the code instead of your job as a contractor to be able to look it up? Between the code I know by heart and the stuff I know how look up I know way more of the code that's relevant to my work than almost every inspector. On the rare occasions that a mistake or a borderline interpretation happens in my work, the inspector usually doesn't notice.

While I truly appreciate you going through the trouble of finding these Plumbing Code sections, I just want to add that I too found them before I posted this in the Forum. Why should I have to slowly scroll through NSPC to find the section I'm looking for ? I asked a simple question of the Code official and expected a simple answer - not "Go look it up in the Code book."

I stopped in to visit with the Building Inspector yesterday. I asked her the following questions and got these answers :
Q-1. Can the 3 utilities be installed in the same trench?
A-1. Yes but they have to be separated.

Q-2. How far apart do they have to be separated ?
A-2. I don't know - you'll have to ask the sub-Code official

Q-3. What are the burial depths do the water and gas lines have to be ?
A-3. I don't know - you'll have to ask the sub-Code official

Q-4. Do I have to use tracer wire or ribbon for each utility ?
A-4. I don't know - you'll have to ask the sub-Code official

Are you getting the picture here ? I can simply lay in my PVC feeder conduits at 18" and walk away but I was asked by the HO, who happens to be a close friend of mine, to take charge of the trenching and guidance of the other trades in this installation.

I'll restate my gripe again - I asked a simple question and expected a simple answer. Instead I got brushed off. The inspectors do not want to tell you if you are doing the job right BUT THEY SURE WILL TELL YOU WHEN YOU'VE DONE IT WRONG AND WILL CITE CODE SECTIONS. Why can't I get that info up-front ?

 

[Mystic Pools]

While I truly appreciate you going through the trouble of finding these Plumbing Code sections, I just want to add that I too found them before I posted this in the Forum. Why should I have to slowly scroll through NSPC to find the section I'm looking for ? I asked a simple question of the Code official and expected a simple answer - not "Go look it up in the Code book."

I stopped in to visit with the Building Inspector yesterday. I asked her the following questions and got these answers :
Q-1. Can the 3 utilities be installed in the same trench?
A-1. Yes but they have to be separated.

Q-2. How far apart do they have to be separated ?
A-2. I don't know - you'll have to ask the sub-Code official

Q-3. What are the burial depths do the water and gas lines have to be ?
A-3. I don't know - you'll have to ask the sub-Code official

Q-4. Do I have to use tracer wire or ribbon for each utility ?
A-4. I don't know - you'll have to ask the sub-Code official

Are you getting the picture here ? I can simply lay in my PVC feeder conduits at 18" and walk away but I was asked by the HO, who happens to be a close friend of mine, to take charge of the trenching and guidance of the other trades in this installation.

I'll restate my gripe again - I asked a simple question and expected a simple answer. Instead I got brushed off. The inspectors do not want to tell you if you are doing the job right BUT THEY SURE WILL TELL YOU WHEN YOU'VE DONE IT WRONG AND WILL CITE CODE SECTIONS. Why can't I get that info up-front ?

I agree with you on this and understand your frustration. They should provide you with the correct answer.

Am I to assume the woman you spoke with is the boss of the rest of the inspectors? If so, why wouldn't she contact them or call them into her office and try to get an answer? I guess she doesn't care.
All this time passes with this back and forth BS which prevents you from continuing and finishing which ultimately holds up payment.

Any failures I've had, the inspectors have told what is needed. Some have said "just fix it now and I'll pass you"

I reached out to a plumbing inspector a couple of years ago as I had a question about gas pipe material I needed for some pool side fire bowls/fire features and a fire pit. He told me what was needed and I installed them and passed my inspection. No big deal for him.

 

[wwhitney]

From the information presented in this thread so far, best practices will be more demanding than code requirements for most of the details:

- On depth, if the frost line is 42", give the water line 42" of cover. If you're using PVC conduit give it 18" of cover. The gas line only requires 12" of cover, but that seems low, give it 18".

- On horizontal separation, none seems to be required. But as Action Dave said, why would you want everything stacked on top of each other? Figure out how much horizontal separation you'd need to dig them up separately. 12" o.c.? More?

- And on a ribbon, obviously that's a good idea in each case.

Cheers, Wayne

 

[kwired]

One ditch deep enough for the water and wide enough for whatever else, nothing stacked on top of anything else.

Why would you want to cut up the gas and electric to get down deep enough to repair the water line?

Exactly. even if allowed to be stacked, still put them all at bottom of trench and not 18" above another line

Water and sewer are commonly required to have separation - to help prevent contamination of the water supply should a mishap occur when excavating in the future. Most other things don't really need separation.

 

[petersonra]

I've always been a proponent of 3rd party inspections but my major gripe with inspections is that they won't tell you how to do a job correctly BUT they sure will tell you when you've done it wrong !!!

It is not their job to tell you how to do your job.

 

[petersonra]

On the other hand, 300.3(B) does refer to conductors of a circuit being in the "same . . . trench," so apparently it is necessary to make a judgement as to what a trench is.

Does that mean that if I dig a single 48" wide trench and throw direct bury single conductor cables into it spread across the width, that's fine, while if I dig two 12" trenches separated by 24", and spread the conductors between the two trenches, it's not? : - )

Cheers, Wayne

That is exactly what it means.

 

[kwired]

It is not their job to tell you how to do your job.

few years back our state EI's were having this sort of problem with homeowner's that were filing their own permits where it was allowed. They ended up being a how to service to some extent and was eating up a lot of their time dealing with these unqualified installers that yet were allowed to do these projects, some weren't even planning to live in them when they were done either.

They fixed that problem without even changing any wording in the laws, just taking a hard look at the wording and determining that a new home still under construction is not the owners "primary residence" until it is completed and they move into it. Therefore they can't install wiring on their new home being constructed without further licensing requirements.

 

[goldstar]

It is not their job to tell you how to do your job.

BUT, it seems to be their job to tell you that you've done something wrong and they'll cite the most obscure Code sections that most EI's normally would have no business researching. The builder has been getting his chops busted on this job by the BI on a regular basis from the footing installation to the cinder block to the structure and to the height of the new garage. This is not everyone's first trip to the rodeo, as the saying goes, but the municipality's construction officials have a way of making everyone feel like they are a first year apprentice, just saying.

Simple questions - simple answers - not complicated !!!