MLO panel vs Main Breaker
- Thread starter nizak
- Start date
- Location
- New Jersey
- Occupation
- Journeyman Electrician
Depends. Is there is an OCPD ahead of the panel? If so there is no limit as to the length.
Yes. The Emergency Disconnect Circuit Breaker at the Utility Meter
- Location
- New Jersey
- Occupation
- Journeyman Electrician
Then the conductors going to the panel are feeder conductors so there is no length or nearest the point of entry restrictions.
- Location
- Illinois
- Occupation
- retired electrician
As long as it is marked "EMERGENCY DISCONNECT, SERVICE DISCONNECT" there is no distance as the load side conductors are feeder conductors and not service conductors.
ggunn
PE (Electrical), NABCEP certified
- Location
- Austin, TX, USA
- Occupation
- Consulting Electrical Engineer - Photovoltaic Systems
What difference does it make how/whether it is marked? If there is OCPD, the conductors are a feeder.
wwhitney
Senior Member
- Location
- Berkeley, CA
- Occupation
- Retired
It was a fiat by the CMP in charge of Article 230 for the 2020 and 2023 NEC. The label can make the "emergency disconnect" be considered "not service equipment", which means that you don't need a separate EGC run downstream of the emergency disconnect. This was to facilitate retrofitting an exterior emergency disconnect for existing installs with an interior service disconnect. And this is all going away in the 2026 NEC, it will simply require the service disconnect to be exterior on one and two family dwellings.
I guess a more generous way to put the rules in the 2020 and 2023 NEC is flexibility on the location of the MBJ. If there is an exterior emergency disconnect, you are still allowed to install the MBJ on a downstream panel that meets the location requirements for a service disconnect.
Cheers, Wayne
- Location
- Illinois
- Occupation
- retired electrician
If it is marked "EMERGENCY DISCONNECT, NOT SERVICE EQUIPMENT" the conductors on the load side are still service conductors even if there is an OCPD. This marking is used when you don't want to relocate the grounding and bonding connections from the inside panel to the outside panel.
which makes this thread even more confusing
'23 NEC 230.7/230.85 Interesting Scenario
Most of TN is still under the '17 NEC so we are just addressing some of the '23 changes as some areas have adopted that version. Scenario has arisen: Question 1: 230.7 prohibits service and non-service conductors to be installed in the same raceway. Under '17n this was pretty cut and dry,'...
forums.mikeholt.com
I have seen new installs where the Contractor has ran just 3 wires from the Emergency Disconnect to the panel inside. They were approved. The GEC in these for instances originated from the panel inside the house.
I’ve been installing with a 4 wire feeder to the panel with GEC from the outside disconnect and bonding screw/ strap attached at that point.
Are both ways code compliant?
Eddie702
Licensed Electrician
- Location
- Western Massachusetts
- Occupation
- Electrician
Yes, for now.
- Location
- Illinois
- Occupation
- retired electrician
Yes...just put the correct marking on the EM disconnect. This was such a screwed up rule, 230.85 goes away in the 2026 and it will simply require the service disconnect for one- and two-family dwellings to be outside, either mounted to the dwelling or within sight.