Two Panels - Two Main Breakers?

pabernathy · September 12, 2014, 1:51pm

Whew…glad you chimed in on that. Double taps can mean two distinctly different things to Electricians and Home Inspectors.:mrgreen:

Your doing a great job here on the boards Robert. Thanks for all you do to help the HI’s. They have a special place in my heart…not all associations mind you…but INACHI yes.

pabernathy · September 12, 2014, 1:55pm

Robert_Meier:

Deciphering this type of services is tricky because of many different variables when you have two service disconnects. According to 230.40 when you have only one drop or underground service lateral you have only one service. In this case you have one service with two service disconnecting means (2-200 amp CB’s) grouped in one location.

The tricky part is based on the size of the conductors feeding the meter enclosure and the size of the conductors feeding the two service disconnects. Since the 2-200 amp service disconnects do not individually carry the entire load of the structure their associated service entrance conductors must be sized according to 310.15(B)(16) which would be #3/0 copper or #4/0 aluminum. {180 amps up to next standard size 200}

Although #4/0 Al in T310.15(B)(7) is permitted for 200 amps technically the table cannot be used. Also for the “next size up rule” {240.4(B)} to be used the connected load cannot exceed the ampacity of the conductor in this case 180 amps.

Simple.

Yep…and then the age old argument begins in terms of the verbiage (in terms of the panel setup being shown by the OP) “for service conductors supplying the ENTIRE load associated with a one-family dwelling” and I will stop at that one. Would each SE Cable(probably Cable) meet the intent of 310.15(B)(7)…or better said does each panel’s service conductors supply the entire load…nope.

jbravo2 · November 4, 2020, 2:21pm

So in this case the home would have 350 Amp service?