nema 14/30 or 14/50

webdriverguy

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#1
Hi Guys,

I am still trying to figure out my charging situation so got a few quotes. I currently have a panel rated at 125 amps.

Here are the two quotes I got -

1) electrician said he can only install a 30 amp breaker. I can charge at 22 miles per hour with this setup. Total cost of install $893

2) another electrician wants to add a 100 amp sub panel and wants to charge $1800. With this setup I can get a 50 amp breaker and could charge at 30 miles/ hr or higher.

I am leaning towards option 1 since my commute is only 10 miles per day and I charge one or two times a week overnight to get back at 90% soc on trickle charging. Is $893 a decent quote for nema 14/30 install? I have no idea so decided to post here. Also would like to mention that I have a supercharger opening a mile away from my home by end of year (per Tesla’s website)
 

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GDN

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#2
Given your daily need for charging doesn't seem like you need any more than the 30 amp breaker, but is there any reason you would want to future proof it now? What would it cost extra to go ahead and pull a heavier duty wire to support the 50 amp breaker (I think a 6 ga wire) and then you could just add the panel if needed and bigger plug down the road. If you only pull the 10/3 wire and want to ever upgrade in the future to the 50 amp you'll have to pull wire again to support it.
 

Lovesword

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#3
Was just about to say the same @GDN.
Another benefit of the 14-50 is resale value. A lot of tooling uses 14-50 (None that I use myself mind you) but someone interested in your home could be. Not the nearly $1k, but the value of having it for someone on a walk through. It can tip the scales on a sale (EV owner or not).
 

GDN

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#4
Yep - even thinking down the road, what if you add a second EV or Model 3. I don't fully understand the WC, but I know multiple can run on the same circuit and split the load, so could run 2 on the 50 amp and deliver charge to both cars without having to plug only one in at a time and still get a decent charging rate, vs sharing one charger between two cars.
 

Lovesword

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#5
A couple other thoughts I randomly am having.

- what other benefits could a 100 amp sub panel do for you? Something to consider.
- I get about 36 miles per hour on 14-50 I believe (?) will have to verify cuz I’ve forgotten*
- when it gets blisteringly cold, your usage will nearly double. I see you’re located in MA.
- not that this makes a big deal, you just charge more often, just an FYI.
- I don’t know the efficiency loss from 14/30 to 14/50...probably minuscule.


* Stella Artois and tomorrow off. :)
 
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#6
With your very long 10 mile commute, I would definetly upgrade your house with a heavy up to your weather head to feed (2) 400amp load centers to support at least (2) 100amp WCs! Jus' kiddingo_O. Shucks, with your commute, a dedicated 5-20 (7mph) or possibly an overkill 6-20 (15mph) will easily suffice. I deployed a 14-30 (18mph on an S) for 5.5 years with 80 and 160-mile commutes. If I had a 10 mile commute, I would only charge to 60%, but that’s a topic for another day with a bunch of pushback from the armchairs.

Good-luck !
 

agastya

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#7
Didn't see any information about how long your run is from the panel. The cost of 6/3 wire is ~ 2x the cost of 10/3 wire - so that adds up if there is a long run. Also, if you plan to charge only with the UMC gen 2, the max it can draw is 32A, so a breaker of 40A will suffice.

Given your low commute, you can easily make do with trickle charging at 5-15, but this only provides with 75% charging efficiency. Any NEMA 240V outlet will increase the charging efficiency to at least 90%... this increase to 90-95% charging efficiency I think is reason enough for everyone to get a 240V charge point setup for use.
 

webdriverguy

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#8
Didn't see any information about how long your run is from the panel. The cost of 6/3 wire is ~ 2x the cost of 10/3 wire - so that adds up if there is a long run. Also, if you plan to charge only with the UMC gen 2, the max it can draw is 32A, so a breaker of 40A will suffice.

Given your low commute, you can easily make do with trickle charging at 5-15, but this only provides with 75% charging efficiency. Any NEMA 240V outlet will increase the charging efficiency to at least 90%... this increase to 90-95% charging efficiency I think is reason enough for everyone to get a 240V charge point setup for use.
The run would be about ~15 feet
 

webdriverguy

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#9
Given your daily need for charging doesn't seem like you need any more than the 30 amp breaker, but is there any reason you would want to future proof it now? What would it cost extra to go ahead and pull a heavier duty wire to support the 50 amp breaker (I think a 6 ga wire) and then you could just add the panel if needed and bigger plug down the road. If you only pull the 10/3 wire and want to ever upgrade in the future to the 50 amp you'll have to pull wire again to support it.
Thank you. The suggestion is great I am going to ask the electrician if he could do that.
 

webdriverguy

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#10
With your very long 10 mile commute, I would definetly upgrade your house with a heavy up to your weather head to feed (2) 400amp load centers to support at least (2) 100amp WCs! Jus' kiddingo_O. Shucks, with your commute, a dedicated 5-20 (7mph) or possibly an overkill 6-20 (15mph) will easily suffice. I deployed a 14-30 (18mph on an S) for 5.5 years with 80 and 160-mile commutes. If I had a 10 mile commute, I would only charge to 60%, but that’s a topic for another day with a bunch of pushback from the armchairs.

Good-luck !
Yeah I could charge to only 60% but i charge extra to have that more range if I need to any trips of 20miles or more during the week
 

webdriverguy

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#11
A couple other thoughts I randomly am having.

- what other benefits could a 100 amp sub panel do for you? Something to consider.
- I get about 36 miles per hour on 14-50 I believe (?) will have to verify cuz I’ve forgotten*
- when it gets blisteringly cold, your usage will nearly double. I see you’re located in MA.
- not that this makes a big deal, you just charge more often, just an FYI.
- I don’t know the efficiency loss from 14/30 to 14/50...probably minuscule.


* Stella Artois and tomorrow off. :)
Thank you. Future proofing idea is great as well but if I go this route I would just have tesla do it since the cost would be approx the same as the other electricians (~2k for nema 14-50 outlet).
 

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#12
And even more thoughts along the line of @Lovesword and the cold climate, isn't there an a
The run would be about ~15 feet
For only 15' I would definitely go with the bigger gauge wire even if you don't add the sub panel. That increase in cost should be very minimal. If it's more than $50 more then you might still want to get another quote on the job.
 

Ed Woodrick

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#13
Hi Guys,

I am still trying to figure out my charging situation so got a few quotes. I currently have a panel rated at 125 amps.

Here are the two quotes I got -

1) electrician said he can only install a 30 amp breaker. I can charge at 22 miles per hour with this setup. Total cost of install $893

2) another electrician wants to add a 100 amp sub panel and wants to charge $1800. With this setup I can get a 50 amp breaker and could charge at 30 miles/ hr or higher.

I am leaning towards option 1 since my commute is only 10 miles per day and I charge one or two times a week overnight to get back at 90% soc on trickle charging. Is $893 a decent quote for nema 14/30 install? I have no idea so decided to post here. Also would like to mention that I have a supercharger opening a mile away from my home by end of year (per Tesla’s website)
Something doesn't seem quite right here. If you've got capacity to install a 100A subpanel, then you should have capacity to install a 60A breaker. And a 100A subpanel on a 125A panel doesn't seem quite right. To do this right, the electricians should have come in, looked at the panel and done some calculations. If they did the quote without that, then they are just giving semi-bogus numbers.

A big part of the cost is how far away and how much trouble it is to install the wire. You didn't mention any of this.
 

webdriverguy

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#14
Something doesn't seem quite right here. If you've got capacity to install a 100A subpanel, then you should have capacity to install a 60A breaker. And a 100A subpanel on a 125A panel doesn't seem quite right. To do this right, the electricians should have come in, looked at the panel and done some calculations. If they did the quote without that, then they are just giving semi-bogus numbers.

A big part of the cost is how far away and how much trouble it is to install the wire. You didn't mention any of this.
Hi Ed,

The run is ~15 feet. I am know that knowledgeable in this area but I think for the second quote they do want to upgrade the service as well to add the 100A subpanel.

Attaching the second quote
 

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MRinPDX

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#16
Hi Guys,

I am still trying to figure out my charging situation so got a few quotes. I currently have a panel rated at 125 amps.

Here are the two quotes I got -

1) electrician said he can only install a 30 amp breaker. I can charge at 22 miles per hour with this setup. Total cost of install $893

2) another electrician wants to add a 100 amp sub panel and wants to charge $1800. With this setup I can get a 50 amp breaker and could charge at 30 miles/ hr or higher.

I am leaning towards option 1 since my commute is only 10 miles per day and I charge one or two times a week overnight to get back at 90% soc on trickle charging. Is $893 a decent quote for nema 14/30 install? I have no idea so decided to post here. Also would like to mention that I have a supercharger opening a mile away from my home by end of year (per Tesla’s website)
I went with the 14/50 since it gave me a faster charge, better resale as some others have mentioned and I didn't have to buy a new adapter for my UMC (it comes with two adapters right). Are you planning on buying a wall charger? If so, then the sub panel makes sense. It may still make sense if your existing panel cannot accommodate 40amps (32amps - 80%) for your UMC. I had a 50amp breaker installed (they moved some other breakers around to physically/electrically accommodate it) and a few feet (< 5 feet) of wiring to a 14/50 outlet for $300.
 
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webdriverguy

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#17
I went with the 14/50 since it gave me a faster charge, better resale as some others have mentioned and I didn't have to buy a new adapter for my UMC (it comes with two adapters right). Are you planning on buying a wall charger? If so, then the sub panel makes sense. It may still make sense if your existing panel cannot accommodate 40amps for your UMC. I had a 40amp breaker installed (they moved some other breakers around to physically/electrically accommodate it) and a few feet (< 5 feet) of wiring to a 14/50 outlet for $300.
Not planning to buy the wall charger
 

webdriverguy

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#18
I went with the 14/50 since it gave me a faster charge, better resale as some others have mentioned and I didn't have to buy a new adapter for my UMC (it comes with two adapters right). Are you planning on buying a wall charger? If so, then the sub panel makes sense. It may still make sense if your existing panel cannot accommodate 40amps for your UMC. I had a 40amp breaker installed (they moved some other breakers around to physically/electrically accommodate it) and a few feet (< 5 feet) of wiring to a 14/50 outlet for $300.
Also 300 is a very good rate
 

MRinPDX

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#19
Also 300 is a very good rate
One correction, I got a 50amp breaker (w/ Nema 14/50 outlet) so I get 40amps out which makes sure I am getting the max amps out of the UMC which is 32amp. I would have gone with higher amps breaker with the plan to get the wall charger except I am also thinking of moving so it didn't make sense right now.
 
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#20
I was in a similar situation where I only have a 100 amp panel and enough capacity for 30 amps. I ran 6 gauge wire to the required location just for future proofing and installed a 14-30 outlet. I was a bit worried about whether I should have payed more to upgrade the panel and get higher charging rates but it’s been more than adequate for our needs and I can’t imagine we’ll ever bother to spend the money to upgrade. For reference, my wife often uses the car to get to work and her commute is 80 miles round trip.

Also as others have mentioned, I’d find out more details on that second quote. If your main panel is 125 amps and is near capacity adding a 30 amp circuit, you can’t just fix the problem with another 100 amp sub panel, you have to upgrade the main panel first. In the quote they state they assume the main panel has capacity for 100 amp sub which seems unlikely. Regardless make sure the electricians are doing the load calculations for your house and checking whether the panel is over capacity or not. It’s not simply a matter of adding up the circuits in the panel. To do the calculations correctly you typically use a spreadsheet to add up major appliances in the house, plus the home’s square footage and weight loads according to how likely they are to be running (ie you’d never be running AC and heat at same time so you take higher load of the two). See here for details:

https://ask-the-electrician.com/residential-electrical-load-calculation.html#beginAdv
 
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