Conduit and Nipples - 60% Rule

[harry.irizarry@windmarhom]

Greetings.
By way of confirming my reasoning about the rule in reference. Could 60% rule be considered for nipples (<24in) between a Meter Main Combo and an MDP and/or OCPD enclosure equipment?

 

[infinity]

Yes it would apply to any nipple 24" or less.

 

[LarryFine]

Welcome to the forum.

I did it here, using only 1.5" for the 4-0 al wires.

 

[electrofelon]

Welcome to the forum.

I did it here, using only 1.5" for the 4-0 al wires.

View attachment 2564836

Larry, you forgot the load and line side conductors. I guess if the customer didn't notice you're good .

 

[Tulsa Electrician]

Larry, you forgot the load and line side conductors. I guess if the customer didn't notice you're good .

 

[jap]

Welcome to the forum.

I did it here, using only 1.5" for the 4-0 al wires.

View attachment 2564836

Come on Larry,,, if you're going to line up the connectors, then line up the connectors.


JAP>

 

[Dennis Alwon]

Welcome to the forum.

I did it here, using only 1.5" for the 4-0 al wires.

View attachment 2564836

I was checking on one of my jobs a few years ago when I noticed my helper did the service. New house and we always use 2" between the meter and the panel. For some reason he used 1 1/4" and I have no idea how it got those wires thru. I think it was 4/0 al with a 2/0 neutral but I am not certain. I do know that it was hard taking it apart. I didn't even do the calculation because there was no way it was compliant.

 

[LarryFine]

I didn't even do the calculation because there was no way it was compliant.

I always check when unsure or using an alternate size.

Raceway Fill Calculator

 

[wwhitney]

For some reason he used 1 1/4" and I have no idea how it got those wires thru. I think it was 4/0 al with a 2/0 neutral but I am not certain. I do know that it was hard taking it apart. I didn't even do the calculation because there was no way it was compliant.

For Schedule 40 PVC and XHHW-2 conductors, it was just compliant under the nipple rules: 2017 Table 5 says 2/0 XHHW has an area of 141.3 mm² and 4/0 XHHW has an area of 206.3 mm², for a total of 553.9 mm². While Table 4 says the allows 60% area is 561 mm²

With just 3 conductors in a nipple, it's difficult to actually violate the 60% fill allowance. The worst case fill is 64.6%, for 3 equal size conductors whose diameter is exactly 46.4% of the raceway ID. As soon as the conductor diameter is 44.7% or less, the fill ratio for 3 conductor is 60% or less. See:

Circle packing in a circle - Wikipedia

en.wikipedia.org

Cheers, Wayne

 

[Dennis Alwon]

For Schedule 40 PVC and XHHW-2 conductors, it was just compliant under the nipple rules: 2017 Table 5 says 2/0 XHHW has an area of 141.3 mm² and 4/0 XHHW has an area of 206.3 mm², for a total of 553.9 mm². While Table 4 says the allows 60% area is 561 mm²

With just 3 conductors in a nipple, it's difficult to actually violate the 60% fill allowance. The worst case fill is 64.6%, for 3 equal size conductors whose diameter is exactly 46.4% of the raceway ID. As soon as the conductor diameter is 44.7% or less, the fill ratio for 3 conductor is 60% or less. See:

Circle packing in a circle - Wikipedia

en.wikipedia.org

Cheers, Wayne

Yes, I did the calculation earlier but I just couldn't leave it the way it was.... Something about it said Hack.....