Garage sub-panel. 100a? 200a? How about 125a?

[s219]

Yeah, I agree, I haven't ever needed more amp capacity, but I have frequently needed more slots for breakers.

At my previous house I had to use "skinny" breakers to add a couple extra circuits. That was a 100A service for a 2200 sq ft house.

At our new house, we have a 200A service for a 2900 sq ft house, with a 125A sub panel fed off that to handle the HVAC equipment. Between a barn, a pier, and a generator (input to the panel back-fed through a 100A breaker), I ended up only having a single empty slot in that 200A panel!! Had I predicted that better, or maybe coordinated better with the electrician, I would have asked for a bigger panel or additional panel to leave more empty slots. We're well within the 200A capacity, but lacking for expansion just based on breaker slots.

I am about to add a whole-house surge protector to the breaker panel which eats up two full slots, and that means I need to convert the top two slots over to skinny breakers to free up space (will end up still leaving me with one open slot in the end). Thank god most modern panels are setup for skinny breakers in the last couple slots on each side -- they must know idiots like me will run out of expansion or have to rearrange things to squeeze in that surge protector.

I have quite a few more spaces available on the 125A sub panel if I really get into a pinch, but when I look at the amp requirements of the HVAC equipment it's intended to handle, I don't have capacity for a whole lot.

The other stupid thing is that my panel is on a garage door wall, squeezed into the ~ 24" space between one door and the corner of the house. The power company started enforcing their policy that meters had to be mounted on the front or side of a house, not the rear (which would have been the obvious place and also hidden the meter from sight). And in those locations, the meter couldn't be on a porch or deck, or under a porch or deck, or more than a certain height above ground. The location we ended up with was the least offensive to satisfy their requirements, but that makes it impossible to run new wiring to unless I put conduit on the interior garage wall and then duck back into the wall near the panel. That was fine for my generator install, but for future expansion I am dreading having to deal with that.

So the moral of my story is to put the panel somewhere you can easily run wire to/from it, and make sure the panel is sized with enough spare slots to allow for future expansion. In retrospect, I would make those factors ***** anything else, even if it meant I had an ugly meter on the front of the house, or had to install a dummy main panel and cutoff next to the meter and run heavy wire to the "real" panel somewhere else in a convenient location. In retrospect that's probably what I should have done, but at the time it didn't make sense to have a dummy panel and cutoff and then have to run 200A cable through the walls of the garage to another spot.

 

[PILOON]

OH. shucks just be sure that the breakers protect the circuits.
IMHO any remote garage/shop is well covered with 100 amps or even 60amps unless you are in a full production mode.
How many machines can U operate at one time?
The key is that the circuit protection is adequate for the wire sizing and current.
60 amps should be adequate for any DIY shops.

 

[plowhog]

60 amps should be adequate for any DIY shops.

I'm not so sure about that. My preference in this case was a heated garage with a propane heater. But, a heated garage of this size threw it into a whole different County permitting process-- involving neighborhood survey and approval, etc. Not good. My option was an unheated garage which is easier to permit, but which triggers the plumbing/freezing issue. Even in an unheated garage, they allow electric heat if it is designed for freeze protection, not comfort. As stated above four of those at 20amps each is 80amps. I believe any panel delivers only 80% of rated value, so a 100a panel would deliver 80a and would be maxed out? My electric water heater needs 30a, car lift needs 30a, etc. If the heaters had kicked on, the water heater was running, and I operated the car lift it might exceed capacity?

I think the idea to pull 200a wire, and set a 200a panel is a good route. Connect it to a 125a breaker in the main panel, which will deliver 80% of 125a to the garage. That method won't interfere with the amps I need for the residence. But if I ever needed to go above that (HVAC?) it is all in place. Overkill? Maybe.

Someone suggested adding propane heat after final inspection. But that is flouting the rules so I of course would never do that. :laughing:

 

[jaxs]

"Someone suggested adding propane heat after final inspection. But that is flouting the rules so I of course would never do that."
Someone else said sometimes it's easier to ask forgiveness than permission.

 

[tonyq60]

"Someone suggested adding propane heat after final inspection. But that is flouting the rules so I of course would never do that."
Someone else said sometimes it's easier to ask forgiveness than permission.

If the building is being permitted then call it a "storage building" and then the rules for heating do not apply.

 

[ultrarunner]

Some have said the need for amps keeps increasing... I've found the opposite to be true.

The new in 1995 Hospital Wing uses significantly less energy today than 22 years ago...

Lighting is more efficient, HVAC is more efficient and large power devices are all but gone... each OR has 50 amp dedicated receptacle for surgical lasers... they were used all the time... well up until the mid 2000's... now, the same function lasers plug into a 20 amp hospital grade outlet.

Had to benchmark last year and 19% of panel capacity is my peak... it had been 34% 22 years ago.

I like the idea of the 200 amp panel with 125 breaker... sounds like a good solution/compromise.

As an aside... most of the single family homes I manage have original service... ranging from 30 amp 120v to 400 amp 240v

At one home the tenant paid to have the service increased from 30 amp 120v to 100 amp 240v as they were into tropical fish... put in several large tanks and spent thousands... thing is it didn't last a year... the tenants had failed to calculate the utility bill for all the new equipment.

I often have found people have wild ideas on what they need until they have to foot the bill... and in this case, the tenant could now plug in to their hearts content but learned they could not afford the price... with tiered pricing they were paying as much a 34 cents a kWh...

 

[marchanna]

"Someone suggested adding propane heat after final inspection. But that is flouting the rules so I of course would never do that."
Someone else said sometimes it's easier to ask forgiveness than permission.

If the work is being done under a permit, then I wouldn稚 take the forgiveness approach because it痴 likely that they will force you to correct it.

There is a couple in British Columbia who built a 1.5 million dollar home who skirted the rules on square footage, and now the municipality is forcing them to demolish the home.

If youæ±*e out in a rural area itç—´ easy to do projects without anyone knowing about it, and bend the rules. But once you get a permit, youæ±*e bound by the rules.

 

[plowhog]

The shifting nature of amp draw makes the decision on what to do more difficult. My electrician said I could get a 20a welder if I wanted to weld. That amp draw is less than earlier choices.

And the LED light fixtures will only draw a fraction of what my metal halide fixtures draw in another metal building I have. But, in the end, given the cost for future retro-fit, if that were ever needed, I think I am comfortable with over-engineering a bit at a 125a panel.

 

[buckeyefarmer]

Ive said it before, our farm is feed at 60A total, house, barns, and we use a tombstone welder..

 

[Deere Dude]

They always say, go big or go home.