Conduit body sizing and grounds

[Paulski]

I am trying to plan for the future on a conduit run from my main panel to a garage sub panel, so I want to put in a pull box or conduit body T:

- Run ~8' of 2" FMC to a 2" T conduit body under the house, main panel is recessed in wall so FMC will be behind stucco.
- One side of the T (the 90*) will reduce down to 1 1/2" rigid conduit and run all the way to the garage (parts will need to be buried)
- The other side (straight from the 2" FMC entrance) of the T will be capped off for now (possible run for an electrical car charger at the driveway (opposite side of property from garage)
-Will be running 4g wire from the panel to the garage

Reading how to do pull box calculations, I need 8 times the largest race way: 2" x 8 = 16" length. But a 2" T is only 10" long. Do I need to up size the T?

Also, when I do run 2 circuits, can they share the ground wire, and how would I connect them in the T? Three 4g wires is to big for a wire nut, can I use a 3 wire grounding bar? would there be enough room to fit the grounding bar?

 

[u2slow]

I suggest not using a T. Do a dedicated run for each. Awkward/tight areas are worth pre-rdrilling, leaving space, and/or stubbing some conduit thru. I most often use outdoor-rated cable anyway.

 

[Paulski]

I agree but unfortunately all the other knock outs are used up already.

 

[teamextreme]

Condulets don't follow the pull box rules, you just install the same size condulet as your conduit. If you need to share a ground wire, that becomes problematic in a condulet. Best solution would be change to a pullbox where you can install a ground bar, or many other options of terminal blocks, splices, etc., or run 2 ground wires into the condulet and not share.

 

[Paulski]

Thanks, I think pulling 2 grounds when it comes time will be easier then. My city build code allows for 12 #4g's in a 2" conduit so I should be good

 

[Norcal]

Ground bars are usually 6 AWG or smaller, lug kits are used to adapt them for larger conductors, but depending on the manufacturer two lug kits may be all that can be done, another way is use a 4-port Polaris connector & running a conductor from it to a lug bolted to the can to bond it, removing any paint under it.

 

[ycgoat]

I think pulling through a T will be difficult especially later on with cable already in it.

 

[Paulski]

I am orientating the T so the later pull will be straight and not the turn to make it a little easier. It is also less than 10' away from the main panel, so I could just pull back the first set of wires, than pull all the wires together into the main panel.

If not a good idea, any suggestions on a pull box to use instead of the T?

 

[Norcal]

I am orientating the T so the later pull will be straight and not the turn to make it a little easier. It is also less than 10' away from the main panel, so I could just pull back the first set of wires, than pull all the wires together into the main panel.

If not a good idea, any suggestions on a pull box to use instead of the T?

If your using flexible metal conduit, I would not use plastic, hell if you were nearby I would give you a used one that need to find a home for as need to clean up stuff, been collecting too much ****, came close to kicking the bucket a few months ago & amazing how being close to making a trip to the mortuary can change ones outlook, but still get winded super easy as lungs heal slowly.

 

[Paulski]

If your using flexible metal conduit, I would not use plastic, hell if you were nearby I would give you a used one that need to find a home for as need to clean up stuff, been collecting too much ****, came close to kicking the bucket a few months ago & amazing how being close to making a trip to the mortuary can change ones outlook, but still get winded super easy as lungs heal slowly.

Sorry to hear about your close encounter with the mortuary Norcal, hope your lungs are getting better. I do plan to order a metal one from McMaster Carr, I can't find a 2" T locally and McMaster seems to have the best price, even with shipping

McMaster-Carr

McMaster-Carr is the complete source for your plant with over 595,000 products. 98% of products ordered ship from stock and deliver same or next day.

www.mcmaster.com

 

[alfredeneuman]

A tee is a real PITA when it comes to pulling wire on the hub perpendicular to the other 2.
There isn't enough room to feed the wires.

 

[mike93lx]

Why not use a larger junction box?

 

[Paulski]

something like this? I would have to enlarge the knock outs to 2" and 1 1/2"

McMaster-Carr

McMaster-Carr is the complete source for your plant with over 595,000 products. 98% of products ordered ship from stock and deliver same or next day.

www.mcmaster.com

 

[mike93lx]

something like this? I would have to enlarge the knock outs to 2" and 1 1/2"

McMaster-Carr

McMaster-Carr is the complete source for your plant with over 595,000 products. 98% of products ordered ship from stock and deliver same or next day.

www.mcmaster.com

Yes. It will have to be large, but I bet you won't regret having the space.

 

[Terry D]

I would not use a T. If they are straight through pulls, use a 12x12x4 or a 14x14x4 J-box. Get one with no knockouts so you can put your own in where needed. You will need a knockout set or a hole saw will work, but thet tend to make the hole to large at times. You will be much happier with a J-box. T's have their purpose, but this is not one of them.

 

[alfredeneuman]

If they are straight through pulls, use a 12x12x4 or a 14x14x4 J-box.

Because it's a straight pull with 2"..... It needs to at least 16" long.

1) Straight Pulls. In straight pulls, the length of the box or
conduit body shall not be less than eight times the metric desig‐
nator (trade size) of the largest raceway.
It's the 90 degree portion if the "tee" that only needs to be 12"

 

[Terry D]

Because it's a straight pull with 2"..... It needs to at least 16" long.

1) Straight Pulls. In straight pulls, the length of the box or
conduit body shall not be less than eight times the metric desig‐
nator (trade size) of the largest raceway.

You are correct, I had it backwards