Bend radius for THHN 3/0 wire

[central1ny]

Does anyone know if there is an NEC code for bend radius that applies to 3/0 THHN wire. I would like to use a 2" 90 degree elbow for a PVC conduit run between the electric meter and the panel box. Any problems with this?

 

[Gooch]

Does anyone know if there is an NEC code for bend radius that applies to 3/0 THHN wire. I would like to use a 2" 90 degree elbow for a PVC conduit run between the electric meter and the panel box. Any problems with this?

nope, there is no problem with that assuming the conduit is sized for the wires it'll hold.

 

[central1ny]

In light of that, is it ok to use (2) 90 deg elbows in the conduit run? The planned conduit run is as follows: A piece of PVC runs down out of the meter socket to a 2" LB Conduit body. A PVC pipe runs out of the back of the conduit body through the rim joinst into the basement and then into a 90 degree elbow to make a right turn. From this elbow, another pipe goes to a 90 degree elbow and then a pipe down into the panel box.

Originally, I was planning on using 2" sweeps but the space is tight and using 90 deg elbows would be easier.

 

[Gooch]

In light of that, is it ok to use (2) 90 deg elbows in the conduit run? The planned conduit run is as follows: A piece of PVC runs down out of the meter socket to a 2" LB Conduit body. A PVC pipe runs out of the back of the conduit body through the rim joinst into the basement and then into a 90 degree elbow to make a right turn. From this elbow, another pipe goes to a 90 degree elbow and then a pipe down into the panel box.

Originally, I was planning on using 2" sweeps but the space is tight and using 90 deg elbows would be easier.

as long as the conduit is sized for the wires there is nothing wrong with that.

 

[Norcal]

The LB's may or may not be rated for the conductors the OP is proposing to use, check the markings in the LB prior to installing.

 

[central1ny]

I checked the LB and it is a Carlon E986J which is rated for (3) 3/0 THHN conductors, so I should be good to go. Thanks for the help.

 

[Charles (in GA)]

Originally, I was planning on using 2" sweeps but the space is tight and using 90 deg elbows would be easier.

We are not talking tight 90 degree plumbing elbows here, a 90 degree PVC electrical conduit "elbow" is the "sweep" that you are referring to. Someone correct me if I am wrong.

Code says you have to assemble the conduit and then pull the wire thru it, if you cannot do that, you have the wrong fittings or too small of a conduit, or are doing something wrong.

Charles

 

[central1ny]

We are not talking tight 90 degree plumbing elbows here, a 90 degree PVC electrical conduit "elbow" is the "sweep" that you are referring to. Someone correct me if I am wrong.

Code says you have to assemble the conduit and then pull the wire thru it, if you cannot do that, you have the wrong fittings or too small of a conduit, or are doing something wrong.

Charles

Actually, yes, I was hoping to use the tight 90 degree elbow. Although I do not even know if they sell these specifically for electrical conductors. I do already have the sweeps but due to space constraints, the tight 90 degree elbows would be fit better. Will it be difficult to pull (3) 3/0 THHN conductors through a 2" conduit that has (2) tight 90 deg elbows?

 

[Aceman]

You're going at this all wrong.

Post some pics of your panels so we can help you run this conduit a little better.

 

[mrobins297aaa]

I pulled 3 2/0 conductors and 1 #2 thru a 2" long sweep 90 and about 4' of 2" pipe and it was a *****. I can't even imagine trying to pull what you are doing thru one el let alone two.......just my two cents

 

[central1ny]

This pcture shows the panel and where the conduit will enter the house - circled in red. So the conduit comes in, over, and then down to the panel.

I have one other questions in regards to the conduit. You can see from the picture that the conduit will be hidden on the backside of the visible rafter. I am concerned about future damage from nails and screws so I was thinking of installing some plate metal (junction box covers) between the conduit and the rafter to protect it. Is this reasonable?

 

[Stuart in MN]

I'm thinking an LB fitting where it comes through the wall, followed by a sweep that goes down into the top of the box.

 

[Norcal]

That may be considered excessive conductor distance where the SE cables enters the structure, a number of jurisdictions only allow 5 feet of unprotected cable into the building, realize that there is NO overcurrent protection between the transformer & the line side of the main breaker......

 

[central1ny]

That may be considered excessive conductor distance where the SE cables enters the structure, a number of jurisdictions only allow 5 feet of unprotected cable into the building, realize that there is NO overcurrent protection between the transformer & the line side of the main breaker......

The distance into the house is under 5 feet and I already got approval from the inspector for up to 5 feet. thanks

 

[Aceman]

I'm thinking an LB fitting where it comes through the wall, followed by a sweep that goes down into the top of the box.

I think this is the way to go.

Ideally the panel would be right under the LB, so it'd be a straight shot down into the panel. Less service conductor in the building that way, and you wouldn't have to worry about those nail penetrations from running across the front of that floor joist.

 

[dwilliams35]

You're actually considering running a 3/0 service through what is basically a plumbing 90? As if it could be done, no inspector worth his clipboard in the country would do anything but laugh at it while he's filling out the red tag.. You've got two choices in electrical 90's: a standard, which, off the top of my head, in 2" is around a 12" radius, or a long sweep, which as I remember is about 18-20" and hard as heck to get.