One More County Looks to Update Building Codes to Accomodate Electric Vehicles


120 Just Doesn't Cut It Anymore

120 Just Doesn’t Cut It Anymore

Several counties throughout the US have been updating building codes to require that all new-construction homes be pre-wired for 240-volt charging stations.  It’s a relatively simple upgrade at the time of construction and we feel all building codes across the nation should be updated to support the future of automobiles.

Give Me Some 220 Please

Give Me Some 220 Please

The latest county looking to join the list in Santa Clara county in California’s Bay Area.

It’s reported that Santa Clara supervisors are considering an electric vehicle pre-wiring ordinance that would both to new-construction homes and to remodels.

In addition, Santa Clara hopes to enact one more ordinance that calls for public chargers to be installed at all county-owned parking lots.

County supervisor Dave Cortese, an electric vehicle owner himself, says he supports this additional ordinance:

“The chargers that are across the street seem to be used pretty frequently. It certainly wouldn’t hurt my feelings if there were more on the back lot here.”

According to the DoE, the county currently has 494 public chargers, which may seem excessive, but remember that the Bay Area is a hotbed for electric vehicles, so more units are always welcomed.

Most of the counties that surround Santa Clara already have a pre-wiring ordinance for new-construction homes, so it seems the proposed alteration to building codes in Santa Clara will likely pass with flying colors.

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8 Comments on "One More County Looks to Update Building Codes to Accomodate Electric Vehicles"

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David Murray

I definitely think a 240V charging station will be standard equipment in a new home. But I’m hard pressed to agree with a new law that requires running a new wire and breaker. That would add potentially $200 to the cost of a new home. I would, however, be all for a code that required the garage to have its own dedicated 120V / 20-amp electrical socket. That would be sufficient for most PHEV drivers and many EV drivers. And even for somebody who doesn’t drive a plug-in vehicle, it is always good to have a 20 amp socket in the garage in case you want to use power tools and don’t want to worry about what else is on the circuit.


A 20A dedicated garage circuit is a good idea. However, most basic 120V EVSEs that come with current cars are limited to 12A continuous draw in order to be safe on a typical 15A circuit. So, for most people a 120V 20A circuit is not any more useful.

Believe me, adding $200 to the cost of a newly constructed home or significant remodel is nothing in Santa Clara County. Also, this ordinance will probably only apply to unincorporated areas of the county. If you get your permits from a city within the county, their rules would most likely apply instead.

David Murray

That’s true. But in this case the cost difference between adding a dedicated 15 amp and a dedicated 20 amp is negligible. And some vehicles can actually take advantage of the 20 amp socket. I’ve heard that the Teslas can as well as the new 2013 Leaf with an EVSE mod.

Eric Cote

$200 adds about $0.50 to one’s monthly mortgage payment.


Charging an EV at 120V is pretty pointless nowadays I’d think; it’s unbearably slow and charging efficiency is usually lower.

Anyway, assuming that there is a slot left in the breakers panel, a dedicated 120V 20A circuit can trivially be switched to 240V. Or vice-versa, for that matter, what’s important is that the wiring be there in the first place. This trivial cost during construction will save thousands to owners later (as I’ve painfully found out). Santa Clara got it right.

Electric Car Insider

The cost of adding a 240v circuit to a garage during new construction or remodeling is pretty insignificant compared to adding it later. If David’s estimate of $200 is correct, compare that with a typical retrofit cost of $2,000. of course, if only a small percentage of households use electric cars, it’s not economic. But I do assume that electric will be our default mode of transportation within 10 years, not only because of clean air regulations, but because electric cars will ultimately be cheaper to buy, as well as operate. ICEs will not be able to compete.


That day has already come, thanks to the government incentives.

I drive a Ford Focus Electric that cost me $40K, minus $10K (fed and state incentives), minus an estimated $10K in gas savings (over 5 years or so). That equals a very nice, high-tech, advanced car for only $20K that needs virtually no maintenance. IMO, that is a bargain.

Compare that to a comparable high-trim ICE Focus, which costs well over $20K –*before* paying for 5-years’ worth of gas, oil, and maintenance. And… AND! — it still won’t drive as nicely, and will make you feel a little guilty/dumb for still using gas as you sit in traffic belching out pollutants.

All that, and I haven’t visited a gas station in 6 months. Personally, that feeling is…. wait for it… priceless.


Why are the commentators limiting the wiring to 240V and 20A? Add a 50A plug and breaker (same cost as a 20A breaker) and allow for future higher-current charging systems. If they locate the plug near the breaker (as I did when retrofitting my house), plug and wiring costs are minimal.