I am new to the forum and would appreciate all the help I can get! I live in the Salt Lake City, Utah area, and just bought a home that isn’t that old at all (mid 90’s). I was doing some investigating with the electrical panel and what circuits fed which rooms and by the looks of things it seems to be wired very strange to me.

Bedrooms wired to garage lights, a washing machine tied into an upstairs bedroom. It gets frustrating to turn of breakers and have unexpected power shut off where you weren’t expecting it to go off.

To ask a simple question in a long post, what are the codes/requirements for switching out my electrical panel to hold more breaker slots? It’s an older Square D panel that has 16 slots. I just want to make it cleaner and have circuits and branches going to dedicated areas instead of the botched remodel and crazy jungle I have now.

I don’t want to upgrade my power and don’t think I need to (maybe I’m wrong). My current panel is rated at 100 amps and just switched over to gas dryer and stove so I no longer am using the two 50 amp slots. Which freed up quite a bit of power draw.

Any suggestions on panels, code requirements, and feed back from anyone who had done a project like this before would be appreciated.

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    Welcome to DIYSE. Unfortunately, this is a very broad-ranging question that doesn't fit our format well. It's not at all a simple question, despite your best intent. Please take the tour to learn how you might simplify it for better responses. – isherwood Nov 19 '18 at 20:57
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    Also, you might ask yourself what you stand to gain for your time and expense. I do understand the desire for clarity and organization. With every home I occupy I create a detailed breaker panel map that gets taped to the panel door. With that, unless you have problems with nuisance trips, using the panel for the occasional shutoff is a breeze. – isherwood Nov 19 '18 at 20:59
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    Finally, if you have free slots, a few new home runs to new 15 or 20A breakers, as wire size dictates, might resolve most of your concerns without the need for a new service. – isherwood Nov 19 '18 at 21:01
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    Can you get the model number of the panel? How much space do you have to accommodate a larger panel? – Harper - Reinstate Monica Nov 19 '18 at 21:51
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    With all the thrash that will come from this question a1990 home only has a few things that are lacking in the 2017 code and in my opinion if your home is still standing and has no problems such as a wall of dead outlets you really don't need an upgrade. You changed to gas, are you updating to LED's ? If so your service is fine and the few differences in today's code for dedicated circuits makes no difference at all in the long run unless you want to waste $ on a system that works fine. Maybe changing a circuit or 2 that was 15 amp that you may want 20 amp is not a reason to change everything – Ed Beal Nov 20 '18 at 1:53

Some of us, including me, are huge proponents of large panels, and so are cheering your idea of getting a much larger panel. That may blind at least me to the downsides of such a switch.

A huge amount of the downside relates to how the panel is mounted and accessible. If it's mounted on an unfinished area with easy access to the various cables going in/out, and the main power inlet is in a favorable place to fitting a larger panel,that is quite a different deal than a panel buried in drywall etc.

There is also the option of going with "double stuff" (tandem) breakers that some of us positively hate, because they have performance compromises and foreclose the possibility of putting AFCI breakers on that circuit. With a 16 space panel powering a modern house, quite likely your panel is already full of double-stuffs.

Anyway, to do this, you will certainly need to have the power company turn your power off for the duration, and you should ask your building authority whether you need to pull a permit for a project that is a pure 1:1 unit replacment. They may say no. If they insist, also ask them if as part of the scope they'll insist on any code upgrades. Normally work is grandfathered to the state it was in when it was built, and since you're not remodeling the circuits they shouldn't require, say, AFCI at $50 each.

Also think about whether the wire lengths of branch circuits will require you to frame the new, taller panel upwards or downwards so most cables reach. It is ok to splice with wirenuts to extend wires. You can also end the circuits in junction boxes outside the panel and use extension wires thru short EMT conduit to bring them home. Those boxes are great places to stick $15 GFCI deadfront or livefront receptacles rather than $40 GFCI breakers.

Or add a subpanel

One way to avoid a hard panel change is to fit a subpanel. The subpanel can be right there, or at some other useful location in the house. The sub can be a panel rated at larger than 100A ampacity (to get a respectable number of spaces like 30, it'll need to be >100A rated. 30+16-2 = 44, a workable number of spaces for a house, the -2 is for the subfeed breaker).

If the subpanel and main-sub feeder is also >=100A rated, then you don't need a subpanel breaker - your main panel's main breaker protects the feeder and sub. You tap either off the bottom fed lugs, or they make a "no-breaker breaker" which snaps into a breaker slot but is just lugs.

A slick trick with subpanels is have a conversation with your power company about where else you could fit a main service drop and meter. Place the subpanel in such an ideal location, and get a big 225 subpanel with main breaker (or space for same). Later, when you want more service, get a bigger meter pan, connect it to the new sub, and have the PoCo bring the new, larger service drop to the new meter and retire the old one. Now the sub becomes the main, and the old main becomes a sub.

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