How to test a 220v 20 amp outlet

Reply

  #1  
Old 06-16-19, 09:21 AM
Member
Thread Starter
Join Date: Jun 2019
Location: USA
Posts: 3
How to test a 220v 20 amp outlet

Hi,
I just got a small garage workshop. It has 100 amp service. there are some old 220v lines that I need to change the outlet to a standard dryer outlet. How do I test the outlet to make sure it is grounded. I have one of those testers but that only works in a standard 115v. I also have a multimeter.
Thanks
 
Sponsored Links
  #2  
Old 06-16-19, 09:31 AM
PJmax's Avatar
Group Moderator
Join Date: Oct 2012
Location: Northern NJ - USA
Posts: 51,006
Likes Received: 163
Welcome to the forums.

Is the wiring in conduit or cabling ?
You can use the multimeter set to the AC scale over what you want to measure. Typically that would be a 300v scale but every meter is different.

With a 240v receptacle..... you will measure 240vAC across the two main slots and 120vAC from each slot to the ground pin. For a dryer you will need #10 wiring on a 2P30A breaker.

Pictures are very helpful too...... How-to-insert-pictures.
 
  #3  
Old 06-16-19, 12:38 PM
Member
Thread Starter
Join Date: Jun 2019
Location: USA
Posts: 3
Pic of current outlet

This is the only pic I have and I am not there. The circuit breaker is 20 AMP . I know the outlet is marked 30 amp but it is on a 20 amp circuit.

Name:  220v.jpg
Views: 43
Size:  126.9 KB
 

Last edited by PJmax; 06-16-19 at 02:55 PM. Reason: resized/labeled picture
  #4  
Old 06-16-19, 12:41 PM
Member
Thread Starter
Join Date: Jun 2019
Location: USA
Posts: 3
So if the meter shows a circuit between each main slot and the ground pin I can assume it is appropriately grounded?
 
  #5  
Old 06-18-19, 08:19 AM
CasualJoe's Avatar
Member
Join Date: Jan 2010
Location: USA
Posts: 9,857
Likes Received: 10
So if the meter shows a circuit between each main slot and the ground pin I can assume it is appropriately grounded?
That dryer receptacle doesn't have a ground pin, just two hots and one neutral. If this is just a 240 volt circuit there is no neutral in the circuit, just two hots and probably one ground. You cannot safely run a dryer without having an insulated neutral conductor.
 
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
Display Modes