upgrade service panel

Reply

  #1  
Old 06-18-18, 04:39 PM
Member
Thread Starter
Join Date: Jun 2018
Location: United States
Posts: 2
Received 0 Votes on 0 Posts
upgrade service panel

I just bought an electric car and want to install a charging connector to what once was an electric dryer circuit. That circuit is a 20 amp circuit and the charger connector is a Siemens US2: VC30GRYU unit. Tech specs list 240V X 30A= 702kW. It states I need a 2-pole 40A circuit breaker.

Can that just be swapped out in the panel? Do I really need to go all the way up to 40Amps? Existing Main is a 70 amp 2 pole breaker. Only using lighting and TV in electrical framework with all lighting LED. No dryer or range in electrical service and probably never will be as we switched to gas 6 years ago. No central AC either.

Thanks
 
Sponsored Links
  #2  
Old 06-18-18, 05:12 PM
Member
Join Date: Mar 2010
Location: USA
Posts: 3,755
Received 42 Votes on 40 Posts
Good electrical practice (and the NEC) dictate that for a continuous load the number of amperes may be just 80% of the breaker and wiring rating. So a 30 amp draw needs the 40 amp circuit with 8 gauge wiring. Car charging, I take it, lasts several hours.

Upgrades of this kind (large increase in amps) usually require a load analysis (sample rules and formulas at the back of the NEC). The results of the load analysis may dictate the need for an upgraded panel and service. Usually the new panel and service need a separate permit from the new (car charging) circuit.
 

Last edited by AllanJ; 06-18-18 at 05:42 PM.
  #3  
Old 06-18-18, 06:11 PM
Member
Thread Starter
Join Date: Jun 2018
Location: United States
Posts: 2
Received 0 Votes on 0 Posts
Thanks for your quick reply. Yes, charging takes a while. About 8-10 hours on 120 and around 4-5 at 240. Quick charges at 440 take about 1/2 hour to 80%.
 
  #4  
Old 06-18-18, 07:08 PM
ray2047's Avatar
Member
Join Date: Mar 2006
Location: USA
Posts: 33,597
Received 13 Votes on 11 Posts
That would be 480v nominal and three phase. That would be expensive if you could even get it at a residential location.
 
  #5  
Old 06-18-18, 08:00 PM
Member
Join Date: Jun 2012
Location: USA
Posts: 1,436
Received 16 Votes on 14 Posts
You stated that your main is 70 amps. That is unusual. Post a picture, please as you may have a larger panel or something else going on.

There are other car chargers that you can re-configure to use a smaller circuit but the one you mentioned is not one of them.

Most dryers are set up to use a 30 amp circuit. With that they can use a 20 amp car charger.
 
  #6  
Old 06-18-18, 08:00 PM
pcboss's Avatar
Forum Topic Moderator
Join Date: Jul 2002
Location: Maryland
Posts: 14,996
Received 39 Votes on 34 Posts
Your dryer circuit was too small for the dryer, less alone be adequate for the car charger. You will need to run a larger cable and charge the breaker.
 
Reply

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


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