New construction home...what to request from the builder re: electrical

[alapd]

As long as you know that the electrical panel is in the garage, your plan will work out fine. However, my main panel is on the other side of the house and it would be 5X the cost for me to install my two 50 amp circuits today compared to when the walls were open during construction.

Yup I am positive of it. It is in the garage very near where I want my outlet to be.

 

[Shock-On-T]

Fat copper.
Make sure the wire gauge from meter box to car is sufficient. Voltage drop-off is a risk with a long line if the gauge is too small.
So much easier if garage is close to meter box.

 

[Dameon]

Lot of talk about voltage drop over "long" distances. Having done electrical work for 20 years, if your run is shorter than 200', I wouldn't bother calculating drop.

110/220 vs. 120/240 - Yes, it is just nomenclature. Depending on your power company, your distance to the sub station and the efficiency of your switch gear, it could be (or should be) between 230-240 at your panel.

As stated, amps are the factor, but voltage does play a role. watts = volts times amps (w=va). If the voltage drops, the amps must increase to generate the watts required. This is how fires occur.

In conclusion, if none of this makes sense, get a professional to do it and don't necessarily trust the first "professional" you talk to. I've seen a lot of folks calling themselves professional that can't explain Ohm's Law. :roll:

 

[tga]

In conclusion, if none of this makes sense, get a professional to do it and don't necessarily trust the first "professional" you talk to. I've seen a lot of folks calling themselves professional that can't explain Ohm's Law. :roll:

I once saw a ceiling-mounted garage opener outlet that was installed by a "professional" that had hot connected to the ground pin.

I discovered it when I tried to hang a (grounded) metal trouble light from one of the opener's mounting straps. The fireworks were quite surprising, to say the least.

They ran 14/3 to a porcelain socket with an integrated outlet for the opener, but ran the red hot to the ground screw (?).

Just because they're a professional, doesn't make them competent!

 

[tga]

Oh, and as others have pointed out, a 100A subpanel in the garage is the way to go for future expandability.

 

[Dameon]

They ran 14/3 to a porcelain socket with an integrated outlet for the opener, but ran the red hot to the ground screw (?). Just because they're a professional, doesn't make them competent!

Anyone using 14 gauge wire (and hopefully 15 amp breakers!) should be questioned. Using 14 gauge wire with 20 amp breakers should be reported.

When I built my house, I over engineered almost everything... especially electrical and communications. Since I had plenty of time and was doing everything myself, I was afforded that luxury. I have several thousand feet of Romex and CAT6 wiring in an average size house. I have two 200 amp panels in my garage. One is generator and UPS backed and the other is straight line power. It took a bit of special requests to get 400 amps of residential power. They had to use a somewhat special induction coil meter as the typical meter bases around here are 200 amp only. I ran several 1" PVC pipes into the attic from each panel to allow for future expansion. I Icynene foam filled all my walls, so fishing wires would be basically impossible.

 

[tga]

Anyone using 14 gauge wire (and hopefully 15 amp breakers!) should be questioned. Using 14 gauge wire with 20 amp breakers should be reported.

Yes, I guess I should have written xx/3 or something like that. It was more the 3 wire + ground with the extra hot that was the issue. I honestly don't remember the wire or breaker size - this was 25 years ago.

 

[Ulmo]

In order from cheapest and simplest at first but most expensive in the long run, to most expensive and most comprehensive at first, and possibly not as expensive in the long run, but my suggestions run pretty thick, rich, and suboptimal, so take them with a horse cube of salt:

1. Put 2" conduit from the main electrical circuit breaker service panel area to all the spots where you might install HPWC's. 2" is a lot easier to pull through than 1.5" or 1".
2. Also, run 1" conduit from each charging location to the next one (daisy-chained), for HPWC communication.
3. Use metal conduit for #1 & #2.
   
4. Install a subpanel with as many amps as you can afford for that subpanel (at least 125 but better would be 225) with all the conduits from #1 connected to it. Alternatively, include this in the calcs and sizing for the main service panel or some other well appointed panel near the garaging areas.
5. INSTALL THE BIGGEST AMPERAGE DROP FROM YOUR UTILITY YOU CAN AFFORD. This might cause the utility to use bigger wires and transformers for your home; this is a good thing often, since that means you can charge your car without causing electrical outages and/or brown outs in your home and neighborhood. My volts in my home drop to around 212VAC when I charge my car at 10kW all the way down from 242VAC; the Tesla won't even let me do more than 48 amps even though it's on a 100 amp circuit because of the voltage drop, and I traced the problem to being too far from a small utility transformer with too many homes on it with small wires for the drop from the pole to the home. Do #5 during the initial designs of the home and the initial designs sent to the utility; never give them a version with a smaller installation, so that they are forced to consider higher provisioning. They might try to pass some of those costs on to you; I'm not sure what to say about that except that it may or may not be worth paying.
   
6. Select the actual parking orientations and locations of each electric car you will own in the next 10 years, figure out how you plug them in, and run the conduit from #1 to those exact locations.
   
7. Buy and install HPWC's at the locations mentioned at #6 for all car parking locations and cars you will own in the next 3 years, complete with wiring, circuit breakers, and home run wiring to the main service panel, if separate from the subpanel.
8. Fully insulate the garage. Also, make it finished; might as well make it nice.
   
9. Put in a heat exchanger in the garage and full HVAC node. This is to vent the unhealthy fumes from charging batteries, car parts, and any ICE's you have, all the while making it comfortable. It also makes certain that whatever the weather outside, your car will fully charge as long as the HVAC in the garage is working nominally.
   
10. Never park an ICE in the garage; this will also allow for lower air flow in the heat exchanger in #9 in order to obtain fresh air.

How's that for some ideas?

BTW, the idea behind #8-#10 is that EV's are not as polluting as ICE's, so this opens up more opportunities to have a less isolated venting-type garage like traditional for ICE type garages, and a more room-temperature inside-air type environment. That does mean a few things: insulation underneath the garage concrete (which means this must be specified all the way at the architecting and engineering stages of the property, since they will have to dig down further during the first site excavation in order to make room for said insulation, and same for vertical and horizontal wall specs), and actually never put an ICE in there. That is a whole level of commitment way above and beyond what most people already do, even most wealthy Tesla owners. It's also probably not the most optimal use of money. BUT, I'm advocating it anyway, since it is a shift in the way we think of cars and how much they pollute.

 

[gregd]

INSTALL THE BIGGEST AMPERAGE DROP FROM YOUR UTILITY YOU CAN AFFORD. This might cause the utility to use bigger wires and transformers for your home; this is a good thing often, since that means you can charge your car without causing electrical outages and/or brown outs in your home and neighborhood.

This is likely utility-dependent, but when I did my panel upgrade last December, my utility guy (PG&E) said that it would be their responsibility to upgrade the wires between my meter an their "pole" (an underground junction box, in my case) if the wires weren't already big enough. Fortunately they were, I think, 4-0, good enough for a 225 amp panel, and we only needed a 200 amp one, so we were good.

But two points about this: One, we think the line from the junction box to my house is a direct burial kind (not in conduit), so it would have been a matter of digging up bushes and trees to replace it. Even if in conduit, the conduit was sized for the older (smaller) wires, under older construction codes, and these wires are really really (did I mention really?) stiff. It's not a simple matter of pulling out one set and fishing in a new one. So, some major construction would be involved, on a non-trivial time line.

Second, I asked about the overall effect on the neighborhood (like, what if everyone wanted to do this?), and he said that if, say, I wanted to go to 400 amps service that it could mean a significant disruption to the entire local infrastructure, and that correcting it wouldn't be an automatic thing. I took that as my upgrade could have been either denied or significantly delayed. Again, fortunately, it never came to that, and, as the junction box ("pole") is in the sidewalk right in front of my house, the voltage sag I experience is maybe a volt or so. Looking at the junction box when it was open, I could see that some homes had smaller wiring than I had (the subdivision was built out over many years), so they might be in for a more extensive project. Good news is that they monitor this sort of thing (overall load and balance), so hopefully we'll never get into trouble. But it was clear that over-building the home infrastructure has its limits, not all of which you have control over.

But, you never know what you have until you open the wrapper. Ask.

 

[SMAlset]

Thanks all! Unfortunately with the builder my only options was a 20amp outlet and 60amp outlet at 220v. This didn't make sense to me.

I think I will just have my electrician wire a 14-50 outlet for me after the fact. With the panel already in the garage, it would be a very short run. And this way I know I am getting the proper outlet and voltage for my car. With my UMC then I will get more than sufficient charging speed for my needs, and can sell my HPWC.

When you say UMC are you thinking of using the one provided in the bag with adapters that comes with the car? If so think of buying the corded mobile connector to keep plugged into the wall.

We've been charging at home with the car's UMC one and every home charge is taking the equipment from the bag, adding the adapter and plugging into our 14-50. Then removing and packing up hours later when done. Not that it's a horrible thing to do but you do flex the adapter and plug each time you remove it. Probably long term not the best thing for them. There probably will be times when you get up late and need to leave quickly for work and realize you need to pack it up. Having something in the wall set up to just use is like pulling up to a Supercharger or having an HPWC installed. Not necessary but nice. Just a thought for you.

 

[SDRick]

If your builder is finishing and painting the garage walls, I would have them do the installation.

 

[TexasEV]

When you say UMC are you thinking of using the one provided in the bag with adapters that comes with the car? If so think of buying the corded mobile connector to keep plugged into the wall.

We've been charging at home with the car's UMC one and every home charge is taking the equipment from the bag, adding the adapter and plugging into our 14-50. Then removing and packing up hours later when done. Not that it's a horrible thing to do but you do flex the adapter and plug each time you remove it. Probably long term not the best thing for them. There probably will be times when you get up late and need to leave quickly for work and realize you need to pack it up. Having something in the wall set up to just use is like pulling up to a Supercharger or having an HPWC installed. Not necessary but nice. Just a thought for you.

Why do you do that? There is no reason to put the UMC in the car unless you're taking a long trip. Especially as you live in the Bay Area which probably has the highest concentration of public charging stations in the country. There are dozens of posts here explaining how most owners keep the UMC plugged in and hanging on a hook in their garage. Mine has been there for 4 years. I unplug about once/month for a trip.

The Mobile in UMC is a capability, not a requirement.

 

[miimura]

This is likely utility-dependent, but when I did my panel upgrade last December, my utility guy (PG&E) said that it would be their responsibility to upgrade the wires between my meter an their "pole" (an underground junction box, in my case) if the wires weren't already big enough. Fortunately they were, I think, 4-0, good enough for a 225 amp panel, and we only needed a 200 amp one, so we were good.

But two points about this: One, we think the line from the junction box to my house is a direct burial kind (not in conduit), so it would have been a matter of digging up bushes and trees to replace it. Even if in conduit, the conduit was sized for the older (smaller) wires, under older construction codes, and these wires are really really (did I mention really?) stiff. It's not a simple matter of pulling out one set and fishing in a new one. So, some major construction would be involved, on a non-trivial time line.

Second, I asked about the overall effect on the neighborhood (like, what if everyone wanted to do this?), and he said that if, say, I wanted to go to 400 amps service that it could mean a significant disruption to the entire local infrastructure, and that correcting it wouldn't be an automatic thing. I took that as my upgrade could have been either denied or significantly delayed. Again, fortunately, it never came to that, and, as the junction box ("pole") is in the sidewalk right in front of my house, the voltage sag I experience is maybe a volt or so. Looking at the junction box when it was open, I could see that some homes had smaller wiring than I had (the subdivision was built out over many years), so they might be in for a more extensive project. Good news is that they monitor this sort of thing (overall load and balance), so hopefully we'll never get into trouble. But it was clear that over-building the home infrastructure has its limits, not all of which you have control over.

But, you never know what you have until you open the wrapper. Ask.

For new construction, I was responsible to pay for the trenching and the service wire from the meter across to and then up the pole on the corner of my property. There was no house on this lot previously. PG&E upgraded the transformer serving my house and my two neighbors from 25kVA to 50kVA about 2 weeks after I moved in, at their cost. I have a 400 amp panel with 320 amp service, but only a single 200 amp breaker at the top of my panel.