KLeary
Member
- Location
- Bridgewater, NJ
I just got off the phone with the local electrical sub-code official (NJ) who is reviewing my plans for a residential solar PV installation. I'm the engineer who signed and sealed the drawings and the electrical contractor who is applying for the permit asked me to talk to the official directly. He told me I have it wrong. Here is the situation:
The existing main panel is a 200A bus panel with a 200A main breaker, single phase, 3-wire, 120/240VAC. There are two proposed solar PV inverter output circuits, each with a 2-pole 15A circuit breaker to be placed in the existing main panel.
The way I read Article 690.64(B)(2) I take the 200A bus, multiply that by 120% and get 240A for the maximum OCPD from all sources. I have a 200A main breaker from the utility and two 15A back-fed branch breakers from the solar PV inverters for a total of 230A, therefore the design complies with that article of the code.
The electrical sub-code official (plan reviewer, electrical construction permit issuer, and possibly one of the inspectors too) informed me that i have it wrong. According to him, the bus can never be smaller than the sum of the OCPD feeding the bus. He referenced the same article and said the 120% refers to the main breaker size, meaning the branch breakers can't exceed 20% of the main breaker size. He rejected the design as is and said to look at the panel and see if the bus is rated 240A. (I've never seen a 240A rated bus, 200A yes, 225A yes, 240A no). Regardless, he said the bus must be at least 230A. I told him that this article doesn't say that, and that specifically this article allows the OCPD to exceed the bus rating and he strongly disagreed.
Before I ask to speak to his boss, I'm just asking the forum for a reality check. Sometimes after reading a code section again and again, it stops making sense. So I could have it wrong, or I'm missing a different article.
Thanks in advance for your help.
-Kevin
The existing main panel is a 200A bus panel with a 200A main breaker, single phase, 3-wire, 120/240VAC. There are two proposed solar PV inverter output circuits, each with a 2-pole 15A circuit breaker to be placed in the existing main panel.
The way I read Article 690.64(B)(2) I take the 200A bus, multiply that by 120% and get 240A for the maximum OCPD from all sources. I have a 200A main breaker from the utility and two 15A back-fed branch breakers from the solar PV inverters for a total of 230A, therefore the design complies with that article of the code.
The electrical sub-code official (plan reviewer, electrical construction permit issuer, and possibly one of the inspectors too) informed me that i have it wrong. According to him, the bus can never be smaller than the sum of the OCPD feeding the bus. He referenced the same article and said the 120% refers to the main breaker size, meaning the branch breakers can't exceed 20% of the main breaker size. He rejected the design as is and said to look at the panel and see if the bus is rated 240A. (I've never seen a 240A rated bus, 200A yes, 225A yes, 240A no). Regardless, he said the bus must be at least 230A. I told him that this article doesn't say that, and that specifically this article allows the OCPD to exceed the bus rating and he strongly disagreed.
Before I ask to speak to his boss, I'm just asking the forum for a reality check. Sometimes after reading a code section again and again, it stops making sense. So I could have it wrong, or I'm missing a different article.
Thanks in advance for your help.
-Kevin
