Vapor Sealed Electrical Boxes Required for 70+ boxes...

[Gopherboy6956]

24" is the minimum depth. I would expect damage to anything else in the trench trying to group everything as expected. 12" is plenty for a ground wire, IMO. Put some caution tape in the trench as a feel good thing to do. Way better to eliminate the safety issue than walk away from it.

I do have plenty of caution tape leftover from running the gas line. Feels good to have a plan.

Now, on to insulation. Lets see if I can get through this without any code violations lol.

 

[Bert_]

This thread got crazy. There are thousands of 3 wire feeders that got ran before 2008. They didn't magically become dangerous after the code change. There are some potential issues but not what some posts are making it out to be.

If you had put a separate meter on the shop you would have got this exact same wire ran and there would be no code issues. Not suggesting you should have done this just making a point that all service drops are three wire. And yes there is occasionally some neutral current flowing on metal pipes/ect between neighboring houses.

 

[mike93lx]

This thread got crazy. There are thousands of 3 wire feeders that got ran before 2008. They didn't magically become dangerous after the code change. There are some potential issues but not what some posts are making it out to be.

If you had put a separate meter on the shop you would have got this exact same wire ran and there would be no code issues. Not suggesting you should have done this just making a point that all service drops are three wire. And yes there is occasionally some neutral current flowing on metal pipes/ect between neighboring houses.

We learn and update. What was once OK can be realized to not be right.

Regardless of what was done before 08, this is new work and is wrong.

 

[Bert_]

We learn and update. What was once OK can be realized to not be right.

Regardless of what was done before 08, this is new work and is wrong.

Would you suggest digging and installing a ground wire for a feeder installed 30 years ago?

 

[mike93lx]

Would you suggest digging and installing a ground wire for a feeder installed 30 years ago?

Sure. If it was my house, I would do it. I'd probably replace the wire if it was the wrong type, too. Wouldn't call it an emergency, but I'd get to it.

Making updates and improvements to things is a pretty normal approach for many. On the flipside, leaving, what you would call, good enough alone is fine.

 

[JohnX14]

This thread got crazy. There are thousands of 3 wire feeders that got ran before 2008. They didn't magically become dangerous after the code change. There are some potential issues but not what some posts are making it out to be.

If you had put a separate meter on the shop you would have got this exact same wire ran and there would be no code issues. Not suggesting you should have done this just making a point that all service drops are three wire. And yes there is occasionally some neutral current flowing on metal pipes/ect between neighboring houses.

I'd leave it and forget about it. If it were a meter disconnect and not service equipment, the 3 wire would be fine. Before Milbank realized their mistake, we had tons of 3 wire service entrances from that same meter socket to the main panel in the house. I probably installed 20 before the mistake was realized and Milbank changed their label in the equipement.

 

[dscheidt]

Would you suggest digging and installing a ground wire for a feeder installed 30 years ago?

Even under the old rules, he'd have to install a four wire feeder, because there's another current path between the two structures.

 

[mm08822]

Today the safety issue is understood.
The OP has additional metallic paths. It isnt just a maybe for a future "what if".
I agree lot's of things need to happen for the safety issue to appear.
What good is saving a few hundred bucks today if you created a booby trap that could kill you one day in the forgotten future.

Add the 4th wire and all can be forgotten from that point onward.

ETA:
As an example:
If there was 10Amps imbalance between L1 and L2, the 200' of 2/0 AL neutral should carry all of that. If there was a parallel path that was the equivalent of #18, then the neutral would only carry 9.88A. The other path(s) could be carrying ~120mA. Many variables exist in the parallel path.
Depending on health of anyone tangled up in the rogue path and duration, >25mA isn't too hard to imagine and their reaction could widely vary.

 

[billconner]

I must be the only one that uses rigid conduit. 6" deep and no separate ground wire. Seemed so utterly simple and easy.

 

[Gopherboy6956]

I must be the only one that uses rigid conduit. 6" deep and no separate ground wire. Seemed so utterly simple and easy.

Man, a 6" deep trench would have been sweet. I rented one of those chainsaw looking trenchers and the thing could barely get to 2' deep.

To make matters worse, our soil here in the red river valley is all **** clay, great for corn, awful to dig in.

 

[mm08822]

Man, a 6" deep trench would have been sweet. I rented one of those chainsaw looking trenchers and the thing could barely get to 2' deep.

To make matters worse, our soil here in the red river valley is all **** clay, great for corn, awful to dig in.

Needed a bigger machine. Life is sweet with a 3' or 4' ditchwitch.....even for a 2' deep trench. Life gets ugly when trying to pull up shale through clay, the extra umph is needed.

 

[mm08822]

I must be the only one that uses rigid conduit. 6" deep and no separate ground wire. Seemed so utterly simple and easy.

OP had 2.5" conduit, albeit oversized. If you can't cut and thead, then not an option.

Even a simple kick w/o hydraulic bender is challenging.

 

[Bert_]

I must be the only one that uses rigid conduit. 6" deep and no separate ground wire. Seemed so utterly simple and easy.

Have you priced rigid?

 

[mike93lx]

Have you priced rigid?

2" rigid is $90 a stick at HD... Pvc is $20. Similar difference for 1.5". Threading aside, guess it depends on soil conditions as to whether or not that would be worth it.

I sure as **** had had times when I'd pay an extra $7 a foot to make a trench shallower

 

[Bert_]

2" rigid is $90 a stick at HD... Pvc is $20. Similar difference for 1.5". Threading aside, guess it depends on soil conditions as to whether or not that would be worth it.

I sure as **** had had times when I'd pay an extra $7 a foot to make a trench shallower

That's about another $1500-$2000 on my average trench. My ditch witch digs through most stuff and if the ground is that bad I could have an excavator come in and dig it for that kind of money.

 

[PCustoms]

I sure as **** had had times when I'd pay an extra $7 a foot to make a trench shallower

For $7 it's a no brainer.

For $70 I'd have to think harder...

 

[mm08822]

For $7 it's a no brainer.

For $70 I'd have to think harder...

OP was at 200'. $70 x 20 = a few ditchwitch rentals.

And then conductor cost if not URD, USE.

 

[mike93lx]

That's about another $1500-$2000 on my average trench. My ditch witch digs through most stuff and if the ground is that bad I could have an excavator come in and dig it for that kind of money.

If you have easy digging soil, it doesn't make sense. For parts of the country, the trench is a lot of work

 

[Bert_]

If you have easy digging soil, it doesn't make sense. For parts of the country, the trench is a lot of work

I'm sure you have bedrock near the surface it add a challenge.

It's hard for me to imagine burying only 6". I usually go 36" or occasionally 48".

 

[mike93lx]

I'm sure you have bedrock near the surface it add a challenge.

It's hard for me to imagine burying only 6". I usually go 36" or occasionally 48".

Not just bedrock.

Clay and large rocks can make trenching terrible. In VA, I can dig a perfect 6" wide trench because there isn't a single rock in my yard but it's super hard or super sticky clay. Back in MA, a trench would have anything from 1' to 6' diameter rocks in the way

 

[Bert_]

Not just bedrock.

Clay and large rocks can make trenching terrible. In VA, I can dig a perfect 6" wide trench because there isn't a single rock in my yard but it's super hard or super sticky clay. Back in MA, a trench would have anything from 1' to 6' diameter rocks in the way

Hard clay has only slowed me down a little. I can usually get the trencher to pull up rocks 6-7" size.

Trenching through a lot of that is hard on the equipment though. I need to weld some more hard facing on some of the teeth before they get too worn.

 

[PCustoms]

OP was at 200'. $70 x 20 = a few ditchwitch rentals.

And then conductor cost if not URD, USE.

I think Mike had a typo was all I was saying

 

[mike93lx]

I think Mike had a typo was all I was saying

Nope.

It's $70 more per 10' stick. $7 a foot

 

[mm08822]

I think Mike had a typo was all I was saying

Per stick vs per foot = same cost when you're buying 10' 'ers.

 

[PCustoms]

Nope.

It's $70 more per 10' stick. $7 a foot

Duh. Misread the first post and didn't go back to look the second time

 

[billconner]

OP had 2.5" conduit, albeit oversized. If you can't cut and thead, then not an option.

Even a simple kick w/o hydraulic bender is challenging.

Seems larger than necessary, but maybe. I worked with 1" for 60 amps - the min for what I needed. Got it dug by hand and installed in a few hours. What's it cost to get a big ditch witch for a half day? The one in the picture is $225 plus an hour and a half drive to pick up and return. Each to their own.

 

[mm08822]

Seems larger than necessary, but maybe. I worked with 1" for 60 amps - the min for what I needed. Got it dug by hand and installed in a few hours. What's it cost to get a big ditch witch for a half day? The one in the picture is $225 plus an hour and a half drive to pick up and return. Each to their own.

how long is the trench?
soil conditions?

 

[mike93lx]

Seems larger than necessary, but maybe. I worked with 1" for 60 amps - the min for what I needed. Got it dug by hand and installed in a few hours. What's it cost to get a big ditch witch for a half day? The one in the picture is $225 plus an hour and a half drive to pick up and return. Each to their own.

$232 for a 4 hr rental on a 48" trencher from home depot for me.

They can be a handful to run at any real depth. Tracked is a must, IMO.

 

[sparky 1971]

I tell my customers that I don't dig; they can take care of it or I can hire someone and it's much more economical if they take care of it but it has to be what I tell them I want. My guy can go up to 6' deep and when he hits a rock that the chain won't pull up, he turns around and digs it up with the hoe on the other end. He also has an excavator if it looks like there might be a problem when doing the initial site survey. I don't have to worry about locates or touching a shovel. I even hired him when I changed over to an underground service at my own house. My days of renting a walk behind trencher ended about 10 years ago due to the lack of a backfill blade.

 

[mm08822]

I tell my customers that I don't dig; they can take care of it or I can hire someone and it's much more economical if they take care of it but it has to be what I tell them I want. My guy can go up to 6' deep and when he hits a rock that the chain won't pull up, he turns around and digs it up with the hoe on the other end. He also has an excavator if it looks like there might be a problem when doing the initial site survey. I don't have to worry about locates or touching a shovel. I even hired him when I changed over to an underground service at my own house. My days of renting a walk behind trencher ended about 10 years ago due to the lack of a backfill blade.

A loooong time ago, I rented one with a backfill blade. I think it was a Ditchwitch. I have not ever found a rental with one since nor even provisions for blade mounting.

Anyone know what happened to them?

 

[Bert_]

I tell my customers that I don't dig; they can take care of it or I can hire someone and it's much more economical if they take care of it but it has to be what I tell them I want. My guy can go up to 6' deep and when he hits a rock that the chain won't pull up, he turns around and digs it up with the hoe on the other end. He also has an excavator if it looks like there might be a problem when doing the initial site survey. I don't have to worry about locates or touching a shovel. I even hired him when I changed over to an underground service at my own house. My days of renting a walk behind trencher ended about 10 years ago due to the lack of a backfill blade.

I've thought about getting a walk behind to use in town. Backfilling with a shovel is why I haven't

 

[sparky 1971]

I've thought about getting a walk behind to use in town. Backfilling with a shovel is why I haven't

The last time I used a walk behind was for a 150ish foot trench that had more 4-6" rocks than I've ever seen, me having to use a shovel to dig them up was strike one. Strike two was when it broke down, the rental company did come fix it that day though. I thought I'd be smart and take my lawn tractor with the snow blade for backfilling; that made it way worse and I ended up working twice as hard with a shovel and rake than if I'd left it alone. Needless to say, that was strike three and I've never consider using one since.

 

[Bert_]

The last time I used a walk behind was for a 150ish foot trench that had more 4-6" rocks than I've ever seen, me having to use a shovel to dig them up was strike one. Strike two was when it broke down, the rental company did come fix it that day though. I thought I'd be smart and take my lawn tractor with the snow blade for backfilling; that made it way worse and I ended up working twice as hard with a shovel and rake than if I'd left it alone. Needless to say, that was strike three and I've never consider using one since.

I was thinking one might be nice for short trenches like 40' ! 150' I'm using the ditch witch.

 

[mm08822]

I was thinking one might be nice for short trenches like 40' ! 150' I'm using the ditch witch.

Ditchwitches come in all sizes. I'm talking 48" walk behind powered track unit - 4" or 6" width depending on need....6" for 4" drainage pipe. There is nice 5' and 6' units with backhoe/blade that have plenty of snot, just not so small.

The worst part is hand backfilling, usually not the digging. Worst yet, the spoils that didn't get back into the trench on day 1 getting rained on.

 

[Gopherboy6956]

Its fun to hear others stories of trenching.

This was my 2nd time renting this model of trencher, a dingo TRX-20, the first time was about 10 years ago for my sprinkler system, and it was the exact same model.

Was just under 200 ft end to end, with a small split at the end for the gas line. Blew through at least 9 sprinkler lines and had to hand dig around 1 that also had all of my valve wires running with it - that was horrible to get to 2' with a 4" space.

I had planned to fill it back in by hand, beacuse it was nice and marbled and granular when I trenched, but with waiting for inspection, my schedule with work, etc it was about 2 weeks before I was ready to fill it all back in. By then it had rained a few times, and my nice clay pellets turned into an amalgamation of horrible sticky mess. I just decided to rent a skidster and call it a day.

 

[billconner]

how long is the trench?
soil conditions?

20' and mostly sandy

ps: may be 3/4. 2 years ago. 60 amps so just 3 no. 6.

 

[Bert_]

Trenching in somebody's backyard in town is probably my least favorite. Always a lot of obstacles.

I know a couple guys that do all their trenching with a mini ex. That works pretty nice in tight spaces. Out in the open this machine, even with a weak hydro, will trench circles around a mini ex.

 

[toplessHO]

I swear the people who write the code books work for the manufacturers/suppliers.

Example : Tamperproof receptacles. I have raise 2 children and am in the process of assisting with 6 grandchildren. The only one who tried to stick something in one of the slots was ME !

Former boss sat on that NFPA board.As a contractor he had nothing to do with manufacturing

 

[theoldwizard1]

Former boss sat on that NFPA board.As a contractor he had nothing to do with manufacturing

Forget MANUFACTURING ! We are talking about SALES !

 

[billconner]

NFPA committees have a maximum of 1/3 of members on the product side. I'm on two and know that is the case on those two at least.