Siemens G2020B1100 Sub Panel Question


Old 10-30-16, 08:41 AM
Thread Starter
Join Date: Oct 2016
Posts: 2
Received 0 Votes on 0 Posts
Siemens G2020B1100 Sub Panel Question


I have a 100 amp sub panel feeding off our main 200 amp panel. I would like to run a 60 amps to my unattached garage and the sub panel is the closest. Looking at the panel, it is full so I have options:

- Add a tandem breaker to free up a space
- Replace the sub panel with a 30 slot one

Obviously the first option is much more economical but after looking at the panel and the type, questions have arisen. First and foremost the type of panel, a 2020. I understand that this allows 20 breakers/poles and no tandem breakers however looking at it what installed, there 4 tandem breakers already in there. All of them were installed by a licensed electrician here in Maine so I'm a bit confused and somewhat concerned because should they be in there and if no, then my options are limited.

Sponsored Links
Old 10-30-16, 09:29 AM
Join Date: May 2015
Location: USA
Posts: 3,138
Received 1 Vote on 1 Post
You are correct, that panel is only listed for 20 circuits. I would not add additional tandem breakers to it.

Before you consider replacing that panel with a larger one to provide ability to run a large circuit to your garage, you should do a load calculation to make sure you won't be overloading the subpanel with the additional large load. You may be better off running a line back to your main panel, even though it is farther.
Old 10-30-16, 10:13 AM
Join Date: Feb 2016
Location: United States, Virginia
Posts: 1,224
Received 27 Votes on 22 Posts
You may know but be sure to research the do's and don'ts of adding a subpanel. Neutral needs to be isolated in sub, sub needs to be fed with 4 conductors, sub needs main disconnect in detached building if having more than 6 breakers, and detached building needs electrode ground system (ground rods). Also make sure you run the proper type feeder wire to garage for under ground use, be it direct bury or in conduit, and to the correct depth.
Old 10-30-16, 10:49 AM
Thread Starter
Join Date: Oct 2016
Posts: 2
Received 0 Votes on 0 Posts
Thanks everyone. The issue with running from my main panel is threefold. One it is much farther (+70'), it is fairly full plus is an old GE panel and finally that part of the house is on a slab so I can run it in the crawl space. It's in the old per of the house and I am not a fan of whomever wired it up not where they placed it. The second issue is I already ran 3" conduit from the garage to an access point near the sub panel. I did not think to check the type of panel as I saw the electrician added tandem breakers I thought I could the same. The conduit I installed a few months ago when I was working on another project and now I am ready to wire the garage, I got to looking at the sub panel.

Replacing the sub panel with a larger one I would contract out as while I could certainly do it, I would want it done neatly and 100% compliant even though two electricians who have worked on that panel at various times have had no concerns about the tandem breakers.

I guess I'll research what my options are.
Old 10-31-16, 11:30 AM
CasualJoe's Avatar
Join Date: Jan 2010
Location: USA
Posts: 10,235
Received 39 Votes on 31 Posts
there 4 tandem breakers already in there. All of them were installed by a licensed electrician here in Maine
It's simple what he did, he installed non-CTL tandem breakers in a CTL panel, a clear intentional code violation. Just because he holds a license does not speak for his integrity. If he were caught doing that in my area he would be fined.

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off

Thread Tools
Search this Thread
Ask a Question
Question Title:
Your question will be posted in: