I recently did an inspection on a 4plex and was a little confused on the SEC around the mast head. There’s some wires tied into one another. Not sure if the were the grounds or some neutrals? Couldn’t access the main panel cause the city has it locked. The sub panels in each unit were also a huge mess. I recommended a license electrician evaluate the sub panels and have the city unlock the service panel and have an electrician look at it. Pictures included.
120/240, 1Ø service. You see 6 conductors exiting the weatherhead, those are parallel conductors, two for each hot and two for the neutral.
This was my first 4plex. I’m assuming this would be a normal configuration? Google has a million different examples.
Thanks for your help.
So are they parallel for two different units? Can two units still pull the same amperage if they are pulling off the same overhead cables?
Not just two, they terminate in the gutter and feed all units from there.
It’s not about being the same, but I know what you mean… The service drop is exposed to air and thus can carry more amps using same gauge than those cables inside conduits, walls, and such, so the answer is yes.
Yes normal just slightly different. Instead of using 3 larger conductors (which is what you’re probably usually seeing) they used 6 smaller ones in groups of two to match the ampacity of the 3 larger ones. These conductors feed the common bus section in the center which then feeds each meter.
You have three pairs and 5 meters, how does that work.?
The paralleled feed is split into the 5 meters.
Looks something like this on the inside. The parallel service entrance conductors feed the utility bus section in the center then internal bus feeds each meter section.
Wow thanks a lot for your help!
Happy to help.
I vaguely remember reading some electrical theory about this. So wire essentially carries more amperage when it’s not sheathed in a housing than when exposed to “air” as you put it?
Yes, due to better heat dissipation being exposed to open air, the power company allows a smaller gauge wire to carry more amps than otherwise would be allowed. If you took the same wire with the same load, ran it inside a wall cavity, it could overheat and melt, short, and or start a fire.