Sub feed Panel

[Paampguy]

Recently started my own electrical contracting business, Have about 30 years of commercial and industrial experience, some residential. Was asked to wire new home for a customer. There will be a 200 amp panel in the garage and a 100 amp sub feed panel in the house. I know I have to use SER cable from the main panel to the sub panel. The cable run from the main panel to the sub panel will be about 150 feet. My question is there a code requirement on how far the sub panel feeder cable can be ran.

 

[LarryFine]

My question is there a code requirement on how far the sub panel feeder cable can be ran.

No, but do keep in mind that the conductors in the 100a feeder must be larger that those permitted for a 100a service.

Welcome to the forum!

 

[goldstar]

Be careful which SER cable you get from the supply house. There are SER's rated at 90 amps and SER's rated at 100 amps.

 

[Coppersmith]

There is no limit on the run length but be aware of voltage drop. You may need to upsize the SER cable depending the actual load in the subpanel to stay within the recommended (and in some places (like Florida) legislated) limit.

 

[infinity]

Recently started my own electrical contracting business, Have about 30 years of commercial and industrial experience, some residential. Was asked to wire new home for a customer. There will be a 200 amp panel in the garage and a 100 amp sub feed panel in the house. I know I have to use SER cable from the main panel to the sub panel. The cable run from the main panel to the sub panel will be about 150 feet. My question is there a code requirement on how far the sub panel feeder cable can be ran.

There is no maximum distance and no NEC requirement to provide voltage drop compensation. A quick look at the Southwire VD calculator came up with #1/0 Al with 100 amp load at 150'.

 

[Knightryder12]

There is no maximum distance and no NEC requirement to provide voltage drop compensation. A quick look at the Southwire VD calculator came up with #1/0 Al with 100 amp load at 150'.

As coppersmith stated, in FLA we have this thing called the Florida Energy Code and that code dictates the 3%, 5% maximum voltage drop. So just make sure the state you're in doesn't have something similar.

 

[infinity]

As coppersmith stated, in FLA we have this thing called the Florida Energy Code and that code dictates the 3%, 5% maximum voltage drop. So just make sure the state you're in doesn't have something similar.

I haven't crunched the numbers but I would guess that using the normal ampacities from T310.15(B)(16) you could get close to 200' before it would make any difference even with a 3% or 5% limit.

 

[petersonra]

Recently started my own electrical contracting business, Have about 30 years of commercial and industrial experience, some residential. Was asked to wire new home for a customer. There will be a 200 amp panel in the garage and a 100 amp sub feed panel in the house. I know I have to use SER cable from the main panel to the sub panel. The cable run from the main panel to the sub panel will be about 150 feet. My question is there a code requirement on how far the sub panel feeder cable can be ran.

Why do you "have" to use SER cable? There are other legal wiring methods to run a feeder.

There is no NEC limit on feeder lengths. There are practical limits.