PT 4: 2024 Garage Build – Electric Feed

With grading complete, I could start on utilities. The primary electric feeder for the house was run underneath the floor plan of the proposed addition, meaning it needed to be relocated prior to digging my new foundation footers.

I contacted our utility, Duke Progress energy, via telephone and a case engineer was assigned. We met for a site visit and walked down my proposal.

About this time in the project, I also began to plan what loads I would need to serve in the addition. Taking a look in my house panel, it quickly became obvious that I would need to upgrade my service. My existing house was on a 200A service, and with no gas in the house, most of that load was already accounted for. In addition, the existing panel was effectively full.

The existing panel was installed in 1998, and is a Cutler Hammer “BR” series device. BR = Bryant from the defunct Bryant Electrical company, who first produced this design. Cutler Hammer was subsequently bought by Eaton, so this style panel and the matching breakers can still be purchased at any store under the Eaton “BR” brand. As I would learn, these color-coded breakers are period correct late 90’s. The electrician I hired attempted to sell me on replacing these as “failure prone Challenger brand” breakers, which I initially fell for, but called that job off before it was executed.

I put together a “wish list” panel schedule in excel to figure out the potential load required for the new addition. This wish list is certainly overkill for a garage that will only ever be used by 1 or 2 persons at a time. What I mean is that, except for HVAC loads, any high-load equipment will only likely ever be used independently. As an individual, I can’t be running my welder at 50a and also running my plasma cutter at 50a. The exception to this is potentially electric car charging.

I originally planned on using a single panel, however I ran into an issue with the 50a outlets. As it turns out, there is no economically manner in which to daisy-chain 50a outlets.

It’s common practice to utilize daisy-chained receptacles in a residential install. There can be an potentially unlimited number of receptacles in a chain, with a single “home run” to the breaker. As long as the load on the sum of all receptacles is less than the breaker, the user will never know.

With 15 or 20a receptacles, they are designed to allow this method of install. The receptacle itself has features designed to accept two hot wires and two neutral wires. For 50a receptacles, this is not the case, and there is no approved and affordable method for connecting the 6 gauge wire required to support 50a circuits (with exception of EV charging and NM-B, its complicated). Even if cost was no object, the physical size of the connection devices would require large junction boxes in addition to the receptacle boxes.

That lead me to the plan to run all 50a drops as individual home runs, and to facilitate this by using a sub-panel. As a bonus, sub-panels are really, really affordable (<$100), and it would shorten the wire runs required for many of the other circuits.

All of that discovery would come in the future however. During the wait for plans, I was focused on getting the main service feed to my house upgraded and re-located. Knowing I would need 200A for the garage, and 200A for the home, meant I would need a dedicated 400A service from the utility company.

On the initial visit, I was talking with the engineer and unwittingly said the magic words of “EV Charging”. I was lead to believe that this made a difference in the classification of the service from Duke. The upgraded service feed to my house would be due to wanting capacity to service these EV chargers, and not because the routing needed to be relocated. As a result, the cost would be zero, with the exception of any boring required to reach the transformer.

After the engineer investigated, I was told that the transformer placed across the street from my lot was serving my home, along with the 4 others in my vicinity. This meant that the transformer would NOT have capacity to upgrade my service. This meant a new transformer would need to be installed, IN MY YARD. I was now off the hook for the boring costs as well!

I signed a right of way release with Duke and the plan was in motion. They would place a transformer in the location I specified, and route the feed to my house as I specified, and the cost was to be zero.

Flags were placed in the specified location, which was dictated based on linear feet of run and paced off with a wheel tape measure. The limit was 400 feet from the panel to the transformer, or wire size would need to increase and the cost would be conveyed on to me.

The utility company subcontracted the install work to Pike Electric, who came and did the work over the course of 2 days. The only hiccup occurred here – the worker digging the trench accidentally cut the path through the proposed new foundation. I was monitoring the progress off-and-on from work via my security cameras, and saw the error. Not having any contact info for Pike, I had no choice but to rush home and interject. By the time I got home, the wire had been burried, meaning the crew had no choice but to abandon it and do a splice somewhere in the feed, after re-digging the trench properly. Hopefully this does not come back to haunt me down the road.

Wire used to feed my transformer: Southwire brand, 25000 volts, TRXLPE insulation, 260 mils. Single aluminum conductor with a copper jacket sandwiched between layers of insulation. This is the “high voltage” wire that feeds in a loop all of the transformers in my neighborhood. Two of these wires enter each transformer, one from each adjacent transformer.

From the transformer, three independent aluminum braided wires are fed to my main meter panel.

With the exception of the trench digging, everything went very smoothly. On the appointed day (23July2024), my electrician and Duke coordinated to shut off my feed, replace my 200a meter with a 400a meter, I called for the electrical inspector, and then my feed was restarted. We spent approx. 8 hours without power to our house. Total cost for this portion of the project: $3000 for the electrician. This included a new 400 A meter base and two 200A main breakers, along with wire to re-feed my existing panel with 4 conductor wire and to separate my grounds/neutrals in the panel. The electrician also drove a new ground rod to meet current code. The permitting process and costs were covered by me directly for an additional $75.