CU to AL & Conduit

[Alwayslearningelec]

Have 4 #350 & 1 #1G in 3" PVC. Doing CU to Al conversion and per the attached pic it looks like the 4 #500 AL can still fit within the 3" conduit.

Why doesnt the calculator let me put in ground size?
Where is NEC would I find new ground size needed for #500 AL?

Thanks.

 

[infinity]

How many amps is the feeder?

 

[Alwayslearningelec]

How many amps is the feeder?

600a

 

[electrofelon]

Have 4 #350 & 1 #1G in 3" PVC. Doing CU to Al conversion and per the attached pic it looks like the 4 #500 AL can still fit within the 3" conduit.

Why doesnt the calculator let me put in ground size?
Where is NEC would I find new ground size needed for #500 AL?

Thanks.

Hit the + and it will give you another row.

 

[augie47]

Referencing the NEC, if it's a feeder, 250.122 is still the location to select the EquipGr based on the breaker size.
If you are changing the EG to AL also, it would be a 2/0

 

[LarryFine]

I like this calculator: http://www.electrician2.com/rveltrain05/rf_calculator.html

It agrees that 3" is large enough for four 500s and one 2/0.

 

[electrofelon]

I like this calculator: http://www.electrician2.com/rveltrain05/rf_calculator.html

It agrees that 3" is large enough for four 500s and one 2/0.

The thing I don't like about that calculator is it doesn't have an allowance for compact conductors

 

[infinity]

600a

So these are parallel sets?

 

[Alwayslearningelec]

So these are parallel sets?

yes

 

[infinity]

yes

How many? The quantity may change the EGC size.

 

[petersonra]

How many? The quantity may change the EGC size.

why would the number of sets change the EGC size?

 

[infinity]

why would the number of sets change the EGC size?

250.122(B) if you increase the size of the ungrounded conductors then you need a proportional increase of the EGC.