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ylmzm

400 Amp service upgrade

ylmzm
10 years ago

We bought an old house (~2500 sqft + 2 car garage) and started upgrading it. The house had an oil furnace and not much appliance. We removed the oil furnace and plan to install a micro-split ductless HVAC system. The house is all-electric.

The following is the list of items (most of them will be installed as soon as service upgrade is completed)
- 1 Outdoor heat pump (4 ton, 9.5kW)
- 3 indoor heat exchangers, each 1.5 ton, 3kW
- 1 double wall oven, 9.5kW
- 1 electric cooktop, 12kW
- Dryer, 7.2kW
- Washing machine, 1.5kW
- Dishwasher, 1.5kW
- Couple of other small appliances, 2kW
- 2 fridges, each ~ 1.5kW
- Water heater, 4.5kW

In garage:
- Lots of power equipment, though not all running at the same time: welder (60 Amp), compressor (30 Amp), miter saw, and other tools.

And outdoor lighting. There are also 3 bathrooms if that makes any difference.

And in the next few years:
- The house will be repiped. We may add tankless water heaters, and if we do, we may need two 18kW units.
- We may add two EV car charging stations.
- We may add solar panels.
- Expand the house (+1000 sqft)

We live in San Francisco bay area and PGE is the utility company. We will ask for a service upgrade anyway, but I am not sure whether it should be 200 Amp or 400 Amp (we have 100 Amp now). Currently, we have a service drop and we will move it to underground. The transformer is 150' away from the main panel on the garage wall. Once all the trench work is done, we will do a lot of landspace work, so it would be very disruptive to re-trench in the future again (if needed).

Given the above information:
(1) Should we go with 200 Amp or 400 Amp service?
(2) Even if we go with 200 Amp service, can we put a larger conduit (or extra conduits), so it would be easier to upgrade to 400 Amp in the future?
(3) What would be the approximate cost for 200 Amp or 400 Amp service upgrade? (excluding trenching work, including PGE cost + main panel replacement by an electrician)

Thanks!

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