Electric question (paging Julie Moriarty!!)

[Rich Engelhardt]

I had an electrician install a sub panel in my garage.
It's only 30 amps though.

Is it possible to increase it to 50 amps just by replacing the breaker(s)?

[Lee Schierer]

You need to identify the panel, the size of the wiring to the panel and the distance to that panel as well as the intended use.

[Wade Lippman]

This might be besides the point, but I installed a 60a subpanel but only had a 30a breaker on hand. I installed it temporarily and found I never needed anything bigger. I was able to run a 3hp cyclone and a 3hp tool just fine on it. Just saying you might want to be certain the 30a is inadequate before doing anything expensive.

[Mark Bolton]

As Lee states, your going to have to identify mainly the size of the wire lead feeding he panel from the main panel. That will be your first indicator of options. Swapping out the sub-panel itself if the wire run to the panel is over-sized would be no major project, but the size of the wire from your main panel to the sub will dictate what your options are. Length of run will be a bit of a factor but much less so. If your current sub panel is fed with something like 10-3 copper, your sunk.

In our experience when small sub panels are run its generally to reduce the cost of the wire run and feed a specific load. Once you get to a point where your feeding more amperage it just becomes more cost efficient to run a 100 amp sub. That threshold here is at 30 amps. You can buy 100amp feeder for only slightly more than 30a so as soon as you break over the 30a mark you just jump to 100 because your pretty much spending the same money for anything between 30 and 100.

[Bill Dufour]

You also have to look at the main panel feeding the sub panel. The main panel may be maxed out and the breaker supplying the sub panel can not be increased with out changing out the power lines from the power company. Home main panels are normally 60, 100, 200 amps. or sometime 400 amp service.
The home I grew up in had 60 amp service. To upgrade to 100 amps the conduit and wire to the weatherhead would have to be replaced with a larger size. The aerial supply lines could supply 200 amps with no upgrade.
Bill D

[Mike Hollingsworth]

My entire 1 man shop runs off of 30 amps. My sander at 7.5hp plus my 2.5 hp dust gorilla don't seem to have a problem.

[Bill Bukovec]

Why don't ask the electrician that installed the panel?

[Kev Williams]

My entire 1 man shop runs off of 30 amps....

I wish mine did! ;)

[Rich Engelhardt]

You also have to look at the main panel feeding the sub panel. The main panel may be maxed out and the breaker supplying the sub panel can not be increased with out changing out the power lines from the power company. That could very well be the reason. Thanks! I'll check that out.

[Rich Engelhardt]

Once you get to a point where your feeding more amperage it just becomes more cost efficient to run a 100 amp sub. That threshold here is at 30 amps. You can buy 100amp feeder for only slightly more than 30a so as soon as you break over the 30a mark you just jump to 100 because your pretty much spending the same money for anything between 30 and 100.Bingo! I bet that's it. I guess my best option here is to convert my dust collector and table saw to 220V instead of their present 120V.

[George Bokros]

Rich, how many things are you running at once? Are you really exceeding the 30 amps?

[Rich Engelhardt]

George,
Table saw & dust collector and overhead lights. T12 florescent.

When I kick on the table saw, the lights almost go out :O

[Bill Dufour]

Absolutely tablesaw and dc should be on 240. That will reduce their needed amps by 50%.
Bill D

[Anthony Whitesell]

I would assume you mean a 30A 220V sub panel was installed. Which means you have 30A of 220V or 60A of 110V (30A from each leg).

A 5HP 20" spiral head planer (Grizzly) requires a 30A 220V circuit. For me that's a big planer, do you have anything that big?

Personally, I too would have wanted the 50A 220V panel. Not that I would ever run a 50A 220V tool, but maybe two tools combined for 50A.

[Julie Moriarty]

I had an electrician install a sub panel in my garage.
It's only 30 amps though.

Is it possible to increase it to 50 amps just by replacing the breaker(s)?

It all depends on the size of the wire feeding the panel. If he installed #10 because that's all he'd need for a 30A sub panel, then the answer is no. If not, what size is the wire and what type of insulation?

[Wade Lippman]

Absolutely tablesaw and dc should be on 240. That will reduce their needed amps by 50%.
Bill D

I am not disagreeing with you, BUT.... If he simply ran them on opposite legs, the result would be identical. (unless one is 120 and the other 240; they would both have to be the same voltage)

[Rich Engelhardt]

If your current sub panel is fed with something like 10-3 copper, your sunk.


If he installed #10 because that's all he'd need for a 30A sub panel, then the answer is noAlrightie then...there's the answer....looks like my goose is cooked. :(.

The feed line is 10-3 - so- - I'm stuck with what I've got.

[Jim Dwight]

The other answers say this but I will say it differently. The breaker must match the wire size. It can be smaller than the safe load on the wire but it cannot be bigger. If you put a big breaker on a small wire you risk overheating and a fire.

[Paul Lawrence]

I would assume you mean a 30A 220V sub panel was installed. Which means you have 30A of 220V or 60A of 110V (30A from each leg).

Rich, you didn't respond to this post. Its likely important. :D

[Darrin Vanden Bosch]

It boils down to, what size wire was used to feed this panel. The breaker is there to protect the wire so it NEEDS to be sized properly to insure the load isn't too much. If the load is too much it can over heat the wire and be a serious fire threat.