SER Cable ampacities and unfinished basements

[bradp0024]

If i'm installing a cable through a basement to feed a 125 amp subpanel would an 1/0 AL SER be correct. I'm looking at the Southwire ampacities tables for SER and it has a column for "Dwellings". Is this only for feeders to main panels feeding the entire load? When is the 90 degree table allowed? I have some bigger cable that I could use, I'm just trying to get a better understanding because the inspector doesn't seem to have a clear answer.

Also, this residential basement has a ceiling grid and tiles hanging about 3" below the the rafters. Can an SER be strapped to the rafters? The basement is being used basically as a garage. There's a little sheet rock covering a few areas and just bare concrete. So, what is our definition of an unfinished basement?

Thanks y'all!

Brad

 

[Dennis Alwon]

You can use 1/0 al for 125 amps as long as the calculated load is less than or equal to 120 amps and your panel is rated at 75C. The use of the 90C column is for de-rating only.

Ser is not a problem above a dropped ceiling

 

[hbiss]

What breaker size are you using in the main panel to feed the sub panel? Probably 100A? Determine your cable size using 100A keeping in mind that you can't derate the feeder, that's only for the service.

You can strap the SER to the bottom of the rafters above the hung ceiling.

-Hal

 

[bradp0024]

The sub is for two 48 amp pottery kilns that won't be run at the same time and they run up to 12 hours but they cycle on and off so i'm thinking that it shouldn't be a continuous load. The sub is rated at 125 but I can feed it from the main with a 100 amp breaker if that's the highest I can go.

That's another thing that I'm struggling with. There's been some talk on this forum about these 48 amp pottery kilns that come equipped with 50 amp 2 pole plugs. I'm thinking that it needs to be fed with a 60 amp breaker but I can't get a 60 amp receptacle that matches up. I'm thinking about cutting off the factory plug and replacing with a 60.

 

[hbiss]

The sub is for two 48 amp pottery kilns that won't be run at the same time and they run up to 12 hours but they cycle on and off so i'm thinking that it shouldn't be a continuous load. The sub is rated at 125 but I can feed it from the main with a 100 amp breaker if that's the highest I can go.

If you can find a 125A breaker for the main panel then use it and size your SER feeder for 125A.

That's another thing that I'm struggling with. There's been some talk on this forum about these 48 amp pottery kilns that come equipped with 50 amp 2 pole plugs. I'm thinking that it needs to be fed with a 60 amp breaker but I can't get a 60 amp receptacle that matches up. I'm thinking about cutting off the factory plug and replacing with a 60.

Where did we say that? Nothing that I can see wrong with using the factory plugs and a 50A circuit.

-Hal

 

[kwired]

The sub is for two 48 amp pottery kilns that won't be run at the same time and they run up to 12 hours but they cycle on and off so i'm thinking that it shouldn't be a continuous load. The sub is rated at 125 but I can feed it from the main with a 100 amp breaker if that's the highest I can go.

That's another thing that I'm struggling with. There's been some talk on this forum about these 48 amp pottery kilns that come equipped with 50 amp 2 pole plugs. I'm thinking that it needs to be fed with a 60 amp breaker but I can't get a 60 amp receptacle that matches up. I'm thinking about cutting off the factory plug and replacing with a 60.

If it doesn't run for more than 3 hours before cycling it is not a continuous load. 48<50. 50 amp circuit and receptacle is fine.