How to test a 220v 20 amp outlet


  #1  
Old 06-16-19, 09:21 AM
M
Member
Thread Starter
Join Date: Jun 2019
Location: USA
Posts: 3
Received 0 Votes on 0 Posts
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
 
  #2  
Old 06-16-19, 09:31 AM
PJmax's Avatar
Group Moderator
Join Date: Oct 2012
Location: Jersey
Posts: 70,075
Received 2,955 Votes on 2,666 Posts
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
M
Member
Thread Starter
Join Date: Jun 2019
Location: USA
Posts: 3
Received 0 Votes on 0 Posts
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: 338
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
M
Member
Thread Starter
Join Date: Jun 2019
Location: USA
Posts: 3
Received 0 Votes on 0 Posts
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: United States
Posts: 11,149
Received 164 Votes on 147 Posts
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.
 
 

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