Hello!

I recently bought a house in Chicago, IL. Our original renovation budget has already been exceeded. My back was messed up when I was rear-ended at a stop light, so I have had to outsource more work than planned. Now I'm trying to figure out how to upgrade the electrical service in the cheapest (but safest) way I can. The city is strict. They will not let me do my own upgrade, so I'll eventually have to hire out this work too. Before I do that I want to be as educated as I can be.

I currently have a 100 amp panel with only one spare breaker. The central AC is on a 60 amp double pole breaker. I want to add an electric booster water heater to service the upstairs bathroom (30 amp @ 220v) and a garage with a 80 amp sub panel (15 amp for lighting, 20 amp outlets and a 40 amp 220v EV charging station). So, the current set-up won't work.

Could I have the new service wire from the meter run to a 200 amp panel and then use the existing box as a sub panel? Or, would I be required to replace the existing box? Any thoughts would be appreciated.

Thanks!

-Mike

 

Welcome to the forums.

It doesn't really make sense to put in a new 200A service with a subpanel next to it.
I would opt for a larger panel.

If you wanted to use that panel as a sub panel like in the garage... that may be doable.

 

If the neutrals and grounds can be separated and the panel is able to be unbonded you can leave the current panel as a sub. It will need a 4 wire feed from the new service panel.

 

On the surface that sounds like a decent plan, but in reality you probably only have a 100 amp meter socket which must be upgraded to 200 amps. I like the subpanel approach because most likely all your wiring is in conduit and the labor to move the existing circuits, in conduit, to a new panel would be nearly prohibitive.

It's time to get a couple estimates from licensed contractors.

 

I don't know that an electrician would charge less or much less to fully replace the panel vs. set it up as a subpanel.

I've never liked the idea of multiple panels unless there's a good reason for it. It gets confusing to find the right breaker, you need to deal with grounding differently, and in your case you'll have an older panel and a newer one, which at some point will need to be upgraded in some way or another.

My personal opinion would be to just replace the panel and the service entry. A straightforward project all/most electricians can do in a few hours.

Just my thoughts though.

-Mike

 

The OP lives in Chicago, Cook County, which requires everything to be in conduit. As CasualJoe wrote, installing a replacement panel where everything is in conduit IS a challenging job. I seriously doubt it could be done in anything less than a day and a half and even then requiring at least two electricians.

However, it being a conduit job the work of separating the equipment grounding conductors (usually just the conduit alone is used) becomes a very minor part of the job, just need to remove the neutral-to-enclosure bond. Placing the new panel adjacent to the old requires only a short conduit nipple with relatively short interconnecting wiring. Adding in the new meter base and often the job can be done without suffering more than an hour or less without power, pretty much whatever time it takes for the utility to change the service drop from the old to the new.

Just because the existing panel is not new does NOT mean it is not fully functional and replacing it based ONLY on age is simply foolish in my opinion.

A PROPER "panel schedule" listing what each and every circuit breaker controls goes a long way towards eliminating confusion. Also, you can use a P-Touch (or similar) label maker to label each end use point (switches and receptacles) as to which CB in which panel is the control. Using smaller clear tape labels is quite unobtrusive.

 

In addition, unless there are some major new loads planned, there is no good reason to upgrade to 200 amps. I think most people would be surprised at how little load they actually have on their service. 30 years ago some insurance companies favored a 200 amp service over 100 amps in older homes simply because it meant to them that the service had probably been updated. Today that doesn't seem to be the case.

 

I would also agree with leaving the existing panel as a sub rather then replacing it all. I also agree with questioning whether a service upgrade is even necessary. As mentioned before, you do not just add up the breakers in the panel(s), it is based on actual load.

 

Prior to my latest revision my service panel, auxiliary panel (loads also served from my generator via transfer switch) and sub-panel totaled over 900 amperes based upon the CB ratings. I have re-connected several items in my shop/garage to connect to the sub-panel which will become a panel for only the shop tools. This sub-panel includes 12,000 watts of electric heaters as well as my two-horsepower air compressor and electric welder so it is likely my total number of CBs now is in excess of 1,000 amperes rating.

Nonetheless, I seriously doubt that I have ever exceeded a total draw of 90 amperes on the 200 ampere main circuit breaker.

Of course all this information is for others reading this thread since the original poster has not returned.

 

Thanks for the replies. Sorry for the delayed response. I had started this last night, but fell asleep before posting...

200 may be overkill, but I'm doubtful the cost of installing a 120 amp panel would be substantially less. Am I wrong? I'm expecting to add quite a bit. I don't have the booster water heater, EV charging station, or garage yet. In the summer I would like to be able to come home to a cool house, charge the car, and take a hot shower without tripping the main breaker.

In the past 3 months I replaced the main 100 amp breaker (after it failed) and 3x 20 amp breakers (with 15 amp breakers due to undersized wire). 1/4 of the house was rewired to get rid of very brittle cloth insulated wire. While the actual box is older (70's), the rest appears to have been updated in the 90's. Everything is very well identified.

I need to replace the cable going from the meter head to the panel since the insulation is in bad shape. My meter is over 6 feet off the ground. ComEd now requires it to be a max of 5 ft. If just replacing the existing cable, the current height is grandfathered in. However, the upgrade requires relocation. So, replacing the meter box is not a big issue.

I've started to reach out to get recommendations for the job. If anyone in the Chicago area has any I am open to ideas.

Thanks again!

-Mike

 

I got some estimated load calculations. It appears that with my desired upgrades I'll be at ~116 amps. Thus the house would require an upgrade. However, I can ditch the booster heater for an on demand re-circulation system. This would put me under 100 amps with a nice margin for safety.

Thanks everyone for your suggestions, comments and making me reconsider what I thought was a necessity. I and my wallet thank you.