Engine block heater triggering gfi
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Fleet Mechanic
Joined: Aug 2017
Posts: 1,274
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From: St Louis Suburbs
Engine block heater triggering gfi
Hey guys.
Anyone ever have a engine block heater that triggers the gfi?
I have used this outlet at least a dozen other times this year. As recently as 2 weeks ago. Today every time I plug it in it immediately trips the gfi. Other items I plug in there work just fine.
Any ideas what is up?
Thank you.
Anyone ever have a engine block heater that triggers the gfi?
I have used this outlet at least a dozen other times this year. As recently as 2 weeks ago. Today every time I plug it in it immediately trips the gfi. Other items I plug in there work just fine.
Any ideas what is up?
Thank you.
Elder User
Joined: Apr 2017
Posts: 523
Likes: 0
From: Eagan, MN
Tuned
Joined: Oct 2016
Posts: 303
Likes: 35
Hey guys.
Anyone ever have a engine block heater that triggers the gfi?
I have used this outlet at least a dozen other times this year. As recently as 2 weeks ago. Today every time I plug it in it immediately trips the gfi. Other items I plug in there work just fine.
Any ideas what is up?
Thank you.
Anyone ever have a engine block heater that triggers the gfi?
I have used this outlet at least a dozen other times this year. As recently as 2 weeks ago. Today every time I plug it in it immediately trips the gfi. Other items I plug in there work just fine.
Any ideas what is up?
Thank you.
If there is a current difference between the hot and neutral, it means there is "leakage" somewhere, and that leakage could be flowing through you.
Some heating elements are known for "leaking" a very small amount of current (but over 5 mA's) which poses no real risk as long as it is going directly back to ground (not through you), but your GFCI won't like it.
When checking your heater element for resistance be sure to check for any continuity between each of the terminals and the heater element body. There should be absolutely no continuity (meter reads OL) between either of the two flat leads and the block heater body, and there should be continuity between the round pin (ground) and the body of the block heater. It doesn't take very much moisture to allow 5 mA's to flow at 120 volts.
Cargo Master
Joined: Feb 2017
Posts: 2,424
Likes: 722
From: Wisconsin
GFCI's work by sensing the current difference between the hot and neutral wires. In other words, if there is 9 amps flowing in the black wire, but only 8.994 amps flowing back through the neutral wire, a properly operating GFCI should trip. They are required to trip by 5 milliamps, which is very low current.
If their is a current difference between the hot and neutral, it means there is "leakage" somewhere, and that leakage could be flowing through you.
Some heating elements are known for leaking a very small (but over 5 mA's) which poses no risk, but your GFCI won't like it.
When checking your heater element for resistance be sure to check for any continuity between each of the terminals and the heater element body. There should be absolutely no continuity (meter reads OL) between either of the two flat leads and the block heater body, and there should be continuity between the round pin (ground) and the body of the block heater. It doesn't take very much moisture to allow 5 mA's to flow at 120 volts.
If their is a current difference between the hot and neutral, it means there is "leakage" somewhere, and that leakage could be flowing through you.
Some heating elements are known for leaking a very small (but over 5 mA's) which poses no risk, but your GFCI won't like it.
When checking your heater element for resistance be sure to check for any continuity between each of the terminals and the heater element body. There should be absolutely no continuity (meter reads OL) between either of the two flat leads and the block heater body, and there should be continuity between the round pin (ground) and the body of the block heater. It doesn't take very much moisture to allow 5 mA's to flow at 120 volts.
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EricPero
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