Okay, so I am thinking about upgrading to 400 Amp service. But if I upgrade, I have a question about my current main panel. If I put an exterior disconnect on the 400 Amp service, I then have to convert my main panel from a 3 wire feed to a 4 wire feed and separate the currently combined grounds and neutrals, correct? Is there an easy way to do that? The wires on the left side of the panel are not long enough to run to the right side, and vise versa. Or do I skip the disconnect and replace my current 100 Amp sub-panel which is right next to my main panel with the second 200 Amp Main? Replacing the sub-panel with the second main seems like a much easier solution. How does one convert a main panel into a sub-panel and keep it reasonably neat?
Rewire Main Panel
- Thread starter Skooterj
- Start date
mark-NJ
Well-known member
If that is correctly stated, then that would imply that the utility company is changing you from a single-phase feed to a 3-phase feed. If that's the case (and at 400A I wouldn't doubt it), then you need to completely replace your existing single-phase loadcenters with 3-phase loadcenters.
This is a bigger job than you might imagine & will almost certainly require a licensed electrician working the permit.
grounded-b
Well-known member
No, what he is saying is that currently he has 3 wires feeding his panel - (2) hots and a neutral. If he converts it to a sub-panel, he will need to separate the neutral from the ground, so he will have 4 wires - (2) hots, a neutral and a grounding conductor.
billconner
Well-known member
Is 400 amp 240 commonly available to a residence?
With everything moving toward energy efficiency, hard for me to imagine needing a 400 amp - 240 or 208 - for a residence. Lots of air conditioning in a big house I guess.
With everything moving toward energy efficiency, hard for me to imagine needing a 400 amp - 240 or 208 - for a residence. Lots of air conditioning in a big house I guess.
wyliesdiesels
Well-known member
That is correct. there is no easy way to do it other than by adding ground bars to both sides of the panel
Here's another thing to consider though. Is this main panel convertible to a subpanel? If its listed for use only as service equipment then its not possible. you would need to check how the neutral bar(s) are bonded.
Do you have pics of the panel with the cover off?
Does your meter pan have dual lugs? how would you feed the new secondary main panel?
totally incorrect. when someone converts a 3-wire main to a subpanel, the neutral bar(s) needs to be isolated and ground bar(s) need to be added if not already installed. This requires an EGC be ran to the panel as well thus making it 4-wire. this has NOTHING to do with 3-phase service
alfredeneuman
Well-known member
Yes it is. (Some current "McMansions" have 600A services)
Those on demand electric water heaters don't help
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billconner
Well-known member
I upgraded last house from 60 amp to 200 and then clamped an amp meter on the feeds. Rarely got above 40 amps. YMMV (or YAMV?)
Since I am only in the consideration phase, I do not have the 400 Amp meter base yet. I've talked with my POCO about it and they are the most relaxed entity on the planet. They do not care what panel, how I wire it, where I put a disconnect. And Indiana is still on NEC 2008. And I think my county(the AHJ) is on about NEC 1901. (Actually I'm pretty sure the inspector only got the job because the previous inspector knew what he was doing and all the local contractors complained enough to the commissioner they fired him and replaced him with the new guy who lets anything slide) So I can pretty much do whatever I want, but I want to do it correct. The POCO is okay with me upgrading the meter box now, even if I don't pay to upgrade the service from the transformer so I can get a double tap 400 Amp meter box. Seems the easiest thing is to replace my 100 Amp Subpanel with the second 200 Amp Main Panel so I don't really have to mess with the current panel other than taking out the 100 Amp breaker feeding the Sub. I just kinda wanted the external disconnect.
Don't know your specific case but most people think they need more power than they really do.
I worked on a 200 that a little overloaded a few weeks ago. It's a bar/restaurant, they have two big fryers that sit on the floor, a small fryer, an electric stove, a griddle, plus a couple of microwaves in the kitchen. They also have two AC units, a couple walk-in coolers, about five chest freezers, all the lights in the building and whatever other miscellaneous stuff I'm forgetting. It would pull 210 amps when everything in the kitchen got turned on from cold. Once things warmed up it was more like 150-160A.
They were having problems tripping the main pretty regularly. It's just a generic residential grade panel. I ended up throwing a new main in it and told them they may want to think about upgrading in the next few years. Honestly if they don't add any more load it probably won't give them problems for a good 10 years.
I worked on a 200 that a little overloaded a few weeks ago. It's a bar/restaurant, they have two big fryers that sit on the floor, a small fryer, an electric stove, a griddle, plus a couple of microwaves in the kitchen. They also have two AC units, a couple walk-in coolers, about five chest freezers, all the lights in the building and whatever other miscellaneous stuff I'm forgetting. It would pull 210 amps when everything in the kitchen got turned on from cold. Once things warmed up it was more like 150-160A.
They were having problems tripping the main pretty regularly. It's just a generic residential grade panel. I ended up throwing a new main in it and told them they may want to think about upgrading in the next few years. Honestly if they don't add any more load it probably won't give them problems for a good 10 years.
Main and subpanel. Adding a detached garage. Eventually finishing the basement. Wife wants tanning bed. Hot tub already wired, but don't have it yet. House it totally electric with geothermal heating pump. Thinking I should have started with 400 Amp. Gonna cost me about $2500 to upgrade now($1200 for POCO to upgrade service line, new 400 Amp meter base, new 200 Amp second main panel) Anyone hiring a work from home job? Need a side gig. lol
No tankless right now. Maybe someday. Well pump, sump pump, septic pump, 2 wall ovens, microwave, 2 fridges, mini fridge, freezer, heat pump with electric resistance back up, garage will have a 4 post lift and maybe a 2 post lift, small compressor, welder, pool, hot tub, tanning bed, 5 bathrooms, 4 bedrooms, home theater, microwave, normal household stuff, normal garage stuff. Maybe a mini split in the new garage Want to add a yard sprinkler system . Who knows when I'll get an electric car. Kitchenette in the basement eventually.
Again, I'd do a load calc. Nothing screams 400A to me.
I mean it's your money. I'd probably do a 400 if this was a new install just to cover the future but I'd think twice for an upgrade.