Upgrading house panel

[matt151617]

I'm buying a house that has a very small 10-space panel with 100 amp service. There are several tandem breakers in the panel and it is very crowded with wires. They ran out of space, and installed a 6-space subpanel off of the main panel.

What's the best option here to make some extra room? Replace the 6-space subpanel with a 20-space subpanel? Add more tandem breakers? I want to avoid replacing the main panel; and being buried in a sea of permits and inspections.

Note- the house has central air, but the dryer, stove, hot water heater, and furnace are all gas. No other 240v circuits or high-draw items.

 

[mike93lx]

If everything in the main is safe and in good shape, yes, you could add a big sub and move stuff over.
More tandems would depend on the panel. It is common to not allow them in all slots. Pictures would help, including the tag on the door and a shot of the guts

 

[thewatusi]

Do a load calculation to see if 100a is sufficient. If it is, replace the 6 space sub panel with a larger one. If 100a isn't enough it's service upgrade time.

 

[75gmck25]

If this is a relatively standard sized house, and you have plans for renovations in the future, I would just bite the bullet and do a 200 amp heavy up with a 30-40 circuit panel. It will cost you about $2000-2500, but will give you plenty of options for future work on the house. If you start renovating, something like a simple kitchen upgrade can lead to needing 4-5 new circuits in an older house.

I have about a 1300 sq ft house, plus 600 square feet in the basement, with gas heat, stove, dryer, and water heater, and it has taken very little time to fill up a 200 amp panel. I already have a sub-panel for the garage, and if I add another bathroom I will have to start swapping in the optional half-size breakers to expand the 30/42 circuit main panel to its max capacity.

Bruce

 

[mike93lx]

If this is a relatively standard sized house, and you have plans for renovations in the future, I would just bite the bullet and do a 200 amp heavy up with a 30-40 circuit panel. It will cost you about $2000-2500, but will give you plenty of options for future work on the house. If you start renovating, something like a simple kitchen upgrade can lead to needing 4-5 new circuits in an older house.

I have about a 1300 sq ft house, plus 600 square feet in the basement, with gas heat, stove, dryer, and water heater, and it has taken very little time to fill up a 200 amp panel. I already have a sub-panel for the garage, and if I add another bathroom I will have to start swapping in the optional half-size breakers to expand the 30/42 circuit main panel to its max capacity.

Bruce

I agree a bigger size panel makes sense, but that doesn't mean a larger service is needed. If the house has gas and doesn't have a substantial cooling load, then 100a is likely more than enough.

 

[brewchief]

For me it would depend on what the old 10 space panel was, if it was something modern I might keep it and add a new sub panel, being that someone thought a 10 space panel would be sufficient for a whole house I suspect it's pretty old. If it's something like a zinsco, federal pacific or pushmatic then it would be gone and replaced with either a new 100 panel with as many spaces as possible or I would take the opportunity to upgrade to a 200 amp service.

 

[matt151617]

Sorry, no pictures as we haven't closed on the house yet. The panel looked to be new-ish, probably within the last 20 years or so. Definitely not a Federal Pacific! My current house had one of those and I had that replaced quickly.

A couple of quick questions if I add a 100 amp subpanel on to the main. First, do I isolate the ground from the neutral? And second, does the supanel require it's own main breaker, or is it ok to only have the feeder breaker in the main panel?

 

[sberry]

You don't need a main in a sub in the same structure. Sounds like you got a good grip on this for starters.

 

[Aceman]

Take a pic with the covers off and I bet we could tell you a few things.

 

[AntonLargiader]

What's the best option here to make some extra room? Replace the 6-space subpanel with a 20-space subpanel? Add more tandem breakers? I want to avoid replacing the main panel; and being buried in a sea of permits and inspections.

Is replacing the main any different permit-wise than replacing the sub? Here in Va. I think it's the same. Adding, moving or replacing a panel needs a permit but if it is replaced in the same location it does not count as "modified circuits" so there's no obligation to bring other things up to current code.