Bare Conductor Size in SER

[czars]

Does anyone know the criteria used by cable manufacturers, such as ALCAN, to size the bare conductor in "3-conductor SER w/bare ground" cable two sizes smaller than the insulated conductors?

 

[dcspector]

Does anyone know the criteria used by cable manufacturers, such as ALCAN, to size the bare conductor in "3-conductor SER w/bare ground" cable two sizes smaller than the insulated conductors?

Hmmm......look at 250.122 as far as EGC sizing. That will be a start on their engineering. Especially 250.122(B) JMO

 

[czars]

Bare Conductor Size in SER

I've looked at 250.122 and those conductor sizes are nowhere near as large as the size of the grounding conductors in the SER for the same currents. Any other ideas?

 

[dcspector]

It is just my opinion. I wonder if it is a ratio of comparison along with 250.122(B)........Heck I am just guessing. I am off today and thought I would keep you company...

 

[czars]

Bare conductor Size in SER

Bare conductor Size in SER

I contacted ALCAN and here is their reply about how or why they size the bare grounding conductor.

"We oversize the ground conductor to allow for parallel runs for larger amperage loads. For example - if you wanted to run an 800 amp service, you could use 4 runs of 250 SER. The ground conductor is 3/0 and would support 800A per NEC Table 250.122.

Also, there are situations where the ground conductor could be used as a neutral."

 

[Pierre C Belarge]

I contacted ALCAN and here is their reply about how or why they size the bare grounding conductor.

"We oversize the ground conductor to allow for parallel runs for larger amperage loads. For example - if you wanted to run an 800 amp service, you could use 4 runs of 250 SER. The ground conductor is 3/0 and would support 800A per NEC Table 250.122.

Also, there are situations where the ground conductor could be used as a neutral."

That is a great marketing scheme...