CHEAPEST exterior car charger circuit?

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LarryFine

Master Electrician Electric Contractor Richmond VA
Location
Henrico County, VA
Occupation
Electrical Contractor
I need a circuit from a house to a detached garage for a car charger, 50a 240v circuit. What is the least expensive wiring method? I expect to run 3/4" or 1" PVC along the wood fence near ground level, not buried.

I'm thinking of using #2 al SE cable, rather than individual copper conductors, even though that might bump up the PVC one size. I'm probably looking at 75/100 feet of conduit to avoid trenching. Opinions, please.
 

JFletcher

Senior Member
Location
Williamsburg, VA
If you can just lay it on the ground, I presume that there is no vehicle traffic... If that is the case, I would look in to see what an aerial drop costs.

There is absolutely no way I would try to pull SE cable through a PVC conduit laying on the ground.

And I think I know where Mac 702 was going... If there is already a circuit out there, you can't legally install the car charger without making your run into a subpanel and feeding the circuit from there.
 
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Coppersmith

Senior Member
Location
Tampa, FL, USA
Occupation
Electrical Contractor
You cannot lay PVC on the ground or close to the ground because it is subject to physical damage, e.g. lawnmowers. I think it's perfectly fine the run the PVC on a fence as long as it is higher than a lawnmower, about 12". Don't forget you will need an expansion fitting or two.
 

ramsy

Roger Ruhle dba NoFixNoPay
Location
LA basin, CA
Occupation
Service Electrician 2020 NEC
I'm thinking of using #2 al SE cable, rather than individual copper conductors... Opinions, please.
Your continuous load may be closer to 40A * 1.25% = #6cu, per Table 310.15(B)(16).

Unfortunately, that table only works for individual conductors, not cable assembly's in conduit.
 

ramsy

Roger Ruhle dba NoFixNoPay
Location
LA basin, CA
Occupation
Service Electrician 2020 NEC
I would never run conduit on a wood fence, if that's what you plan on doing. Fences just don't last as long as conduit.

My area is infested with Associations & other snitches that either complain about any exposed outdoor raceways --including on masonry walls--, report it to Code Enforcement, or badmouth the installer.
 

al hildenbrand

Senior Member
Location
Minnesota
Occupation
Electrical Contractor, Electrical Consultant, Electrical Engineer
I need a circuit from a house to a detached garage for a car charger, 50a 240v circuit. What is the least expensive wiring method? I expect to run 3/4" or 1" PVC along the wood fence near ground level, not buried. . . Opinions, please.
Given that the car charger addition will require the new feeder to replace the existing branch circuit (2017 NEC 225.30), to control cost I'd get aluminum THWN.

In swinging the existing detached garage branch circuit into a new subpanel, a subpanel on a new feeder, will the requirement of 210.11(C)(4) for receptacles on a separate 120 V 20 A branch circuit be invoked? 210.11(C)(4) is NEW to the 2017 NEC.
 

JFletcher

Senior Member
Location
Williamsburg, VA
Given that the car charger addition will require the new feeder to replace the existing branch circuit (2017 NEC 225.30), to control cost I'd get aluminum THWN.

In swinging the existing detached garage branch circuit into a new subpanel, a subpanel on a new feeder, will the requirement of 210.11(C)(4) for receptacles on a separate 120 V 20 A branch circuit be invoked? 210.11(C)(4) is NEW to the 2017 NEC.

Good to know however it is not applicable if Larry is doing this work in Virginia -- we are not on the 2017 NEC, from my understanding we just adopted the 2015 IRC in September. Many of the city and county websites still list the 2012 as what they follow.
 

MAC702

Senior Member
Location
Clark County, NV
I was still picturing conduit along the fence in such a way that the mower blades don't hit the fence. But I agree metallic conduit has advantages here in other ways, as well.

I thought we were just talking about what was approved for physical protection. I can think of plenty of ways to damage exposed RMC, too.
 

Coppersmith

Senior Member
Location
Tampa, FL, USA
Occupation
Electrical Contractor
My area is infested with Associations & other snitches that either complain about any exposed outdoor raceways --including on masonry walls--, report it to Code Enforcement, or badmouth the installer.

HOA's are a whole 'nother thing. Some of them have really stupid (i mean strict) rules. Glad my HOA rules are really weak. I can park several service trucks in my driveway. :)
 

LarryFine

Master Electrician Electric Contractor Richmond VA
Location
Henrico County, VA
Occupation
Electrical Contractor
Thanx for the replies. I went to house today. According to the NFPA site, we're on the 2014 NEC. I have no idea how the IRC affects any of this work.

The run consist's of about 20' in the basement/crawl, 10' under the deck, about 50' along the brick wall, and about 30' inside the garage, panel to receptacle.

The "fence" is actually a brick wall. So, I the PVC must be fastened above ground or buried. I'm thinking buried along the wall, but not full depth. Fletch?

The charger has a 4-prong 50a plug, same as a range. Does the presence of the neutral prong mean I must run a neutral, regardless of whether it's used?

Yes, there is a single 120v lighting circuit in an underground 1/2" rigid conduit, or whatever's left of it. 225.30 is the section prohibiting two feeds, right?

A 50a circuit isn't going into 1/2", so, either abandon it or, if we re-purpose it as lighting, the direction of power must be to and not from the house, right?

So, is a 60a feeder adequate, with either copper in 3/4" or aluminum in 1"? And a 6-space-max panel? Ground rod electrode required as usual, right?

So they make aluminum THWN? As small as #4? I will check locally Monday. I am again looking for the least cost, and I'm still considering #2 al SER.

The SER would let me run the cable unbroken from the house panel to the garage panel, and not require splices where it enters the crawl. Alternatives?

We've discussed occasions where one might put wire in conduit as it's assembled; this is one such example. What size PVC would #2 al SER require?
 

JFletcher

Senior Member
Location
Williamsburg, VA
I'm thinking that if you bury the PVC that it must be at the minimum depths as required by 300.5. if you secure it low to the brick wall, you would probably need schedule 80. Is EMT not an option? With EMT, yeah you're going to pay a bit more, but you don't have to strap it as often or use expansion fittings.

Virginia commercial is on the 2014 NEC. One and two family dwellings still fall under the IRC, which was supposed to go to the 2015 like last July but never did until supposedly this September. generally the IRC has exceptions that make it more slack than whatever NEC version is based on, so building it to 2014 NEC is going to be fine. Larry Fine, even. :D

(Feel free to use that as a new slogan).

In regards to your question about circuit ampacity, I do not know how electric vehicle chargers are rated from the factory... I know that they are considered continuous loads. I would assume that a car charger with a 50 amp plug only draws 40 or less amps, but you know what they say about assumptions...

You will have to run a 4 wire feed in any case because it is a detached building. And you have 120v circuits.

the other possible problem I see with SE cable of any type is running it that far into either building. you could run individual conductors in a smaller conduit and put lbs for Access / pull points where you need them, and pull it all is one long run to avoid splicing the larger conductors.

Eta: with EMT, you may be able to go to a smaller trade size since you can use the Raceway as a ground.
 
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JFletcher

Senior Member
Location
Williamsburg, VA
I did not look at what size conduit you need for number 2 aluminum quadruplex or SE cable, but it is going to be at the very least an inch and a quarter if it were individual conductors. That's going to put you into the realm of needing more or less commercial type equipment to bend any conduit.

1in EMT can accept up to 3 #2 conductors, and it would be possible to bend that with a manual pipe bender.

Three-quarter inch EMT or PVC, you can have up to 4 number 6 conductors, which would give you 65 amps. the charger would have to be 40 amps or less, otherwise it could not be a continuous load on a 50 amp breaker. voltage drop is not an issue at the distance you are talking about.
 

Little Bill

Moderator
Staff member
Location
Tennessee NEC:2017
Occupation
Semi-Retired Electrician
I would use 2-2-4-6 mobile home wire (USE-2). It is cheap and you use it with or without conduit. You could feed it with a 90A breaker to a new sub in the garage since you have to run a new feeder anyway.
 

ramsy

Roger Ruhle dba NoFixNoPay
Location
LA basin, CA
Occupation
Service Electrician 2020 NEC
The charger has a 4-prong 50a plug, same as a range. Does the presence of the neutral prong mean I must run a neutral, regardless of whether it's used?..

Was Red tagged for feeding 240v car charger outlet with 6/2 Romex. Inspector said, while feeder is for a car charger outlet only, a listing violation ocured with NEMA 14-50R "range outlet", since its listed for use with a neutral, and other appliances in the garage could be plugged in there.
 
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