Using dryer outlet for electric car


  #1  
Old 10-31-14, 01:48 PM
J
Member
Thread Starter
Join Date: Oct 2014
Location: United States
Posts: 1
Upvotes: 0
Received 0 Upvotes on 0 Posts
Using dryer outlet for electric car

Hi all,

Looking for a quick double-check from those who know this stuff better than I. We're about to purchase a Leaf, and will upgrade the included charger so that it's capable of fast-charging from our dryer outlet. I already know this is possible with the voltage and amperage we have, so no question there.

But, to share my dryer outlet, this is my plan:
  • Using a new plug, run a 4-wire cord to a 2-gang box
  • Effectively create a Y-shape extension cord by wiring the incoming feeds to a 14-30R plug that will go to my dryer, and to a roughly 12-foot 3-wire extension cord (this will make sense in just a second)
  • My dryer plugs into the 2-gang box and 14-30R, while the extension cord exits the box and goes through a hole in my wall to the outside
  • I connect a L6-20R plug on the end of the extension cord where it exits the wall, and this allows me to plug my charger directly to the extension cord
  • This effectively splits the connection to feed two devices - however, we will never run both devices at the same time.

So two questions, really:

Does the above scenario make sense? Is there anything that I'm doing that's wrong or dangerous?

IF we did screw up and run both at the same time, can anyone confirm that the existing 30 amp breaker would effectively provide a fail safe to ensure that no damage was done?

Thanks all!

Jeramie
 
  #2  
Old 10-31-14, 02:08 PM
pcboss's Avatar
Forum Topic Moderator
Join Date: Jul 2002
Location: Maryland
Posts: 13,970
Received 194 Upvotes on 170 Posts
You cannot use flex cord running through a wall. Also the junction box may not be large enough for the splices.
 
  #3  
Old 10-31-14, 02:10 PM
I
Forum Topic Moderator
Join Date: Feb 2005
Location: Near Lansing, Michigan
Posts: 9,785
Upvotes: 0
Received 45 Upvotes on 43 Posts
Does the above scenario make sense? Is there anything that I'm doing that's wrong or dangerous?
What you're proposing is not a safe or legal solution to the problem. There are a few significant issues:

If the charger unit has a 6-20 plug on it, then it cannot be used on the 30A dryer circuit as the wiring and internal components have been designed for use with a 20A breaker.

The system would be designed such that the car and the dryer together would overload the wiring (see below).

While your terminology is a bit unclear, it sounds like you are proposing using some extension cord or flexible cord, which is not a substitute for permanent wiring methods. When mounting on a garage wall, it would probably make sense to use building wiring in conduit -- some areas may even mandate this.

IF we did screw up and run both at the same time, can anyone confirm that the existing 30 amp breaker would effectively provide a fail safe to ensure that no damage was done?
The breaker should be a last line of protection instead of the primary. The correct solution is to design circuit such that it won't happen.

What really should be done here is to forget the dryer receptacle and run a new circuit from the main panel to the car charger unit. I assume based on the receptacle you described that it would be a 20A, 240V circuit which is a pretty straightforward job. Where is the main breaker panel in relation to the car?

A possible alternative solution would be to replace the dryer outlet with a 30A subpanel which then feeds both the car and the dryer, but this is not an ideal solution. I wouldn't consider this unless it's extremely difficult to pull a new circuit back to the main panel.
 
  #4  
Old 10-31-14, 02:31 PM
dirtydickey's Avatar
Member
Join Date: Aug 2014
Posts: 46
Upvotes: 0
Received 0 Upvotes on 0 Posts
Your going to drop 30 grand on an electric car.... you might want to invest a tiny fraction of that and hire an electrician to do this properly. What you propose is a very poor alternative.
 
 

Thread Tools
Search this Thread
 
Ask a Question
Question Title:
Description:
Your question will be posted in: