Gfci tripping :confused:

[KansasSparky]

I went on a service call with my supervisor to a dental office. They have two sterilizers plugged into the same circuit along with some other small machines, the problem is that they are tripping the gfci that they are plugged into. We put a clamp meter on the circuit and it is pulling 22 amps. We separated the circuit and added another gfci because my supervisor thought that the gfci was acting as a breaker and tripping. We got called out again because they are still tripping but only one of the sterilizers is tripping the gfci?s. Both are brand new gfci?s and the sterilizers pull 9 amps a piece. My thought is that the sterilizer is leaking current which is what is tripping the gfci. Is there anyway to test the machine to check this? And we can't put in a regular duplex because it is within 6 ft of a sink.

 

[brother]

I went on a service call with my supervisor to a dental office. They have two sterilizers plugged into the same circuit along with some other small machines, the problem is that they are tripping the gfci that they are plugged into. We put a clamp meter on the circuit and it is pulling 22 amps. We separated the circuit and added another gfci because my supervisor thought that the gfci was acting as a breaker and tripping. We got called out again because they are still tripping but only one of the sterilizers is tripping the gfci?s. Both are brand new gfci?s and the sterilizers pull 9 amps a piece. My thought is that the sterilizer is leaking current which is what is tripping the gfci. Is there anyway to test the machine to check this? And we can't put in a regular duplex because it is within 6 ft of a sink.

if you know that the receptacles are good, then its the sterilizer that the owner needs to have checked by a 'specialist'. If you are allowed to check the sterilizers, you can meg them.

My guess is that the water/liquid in them is causing the leakage. Ive seen this happen before.

 

[Dennis Alwon]

I would plug one in at a time and see which one is causing the problem. Remember the gfci don't trip on overload so you definitely have a leakage somewhere.

 

[busman]

An AC leakage clamp meter is your best friend in these situations.

Mark

 

[mcclary's electrical]

What code cycle are you on? The 6' rule in the 05 does not apply to "other than dwelling unit"

08' has the 6' rule.

 

[KansasSparky]

We are under the 08 code. We narrowed it down to one machine tripping the gfci but unfortunately the company I work for doesn?t own a megger or a AC leakage clamp meter. And the dental office isn?t to happy because they say it cost about 5 grand for a new sterilizer... not sure what it would cost to repair it if possible.

 

[mcclary's electrical]

We are under the 08 code. We narrowed it down to one machine tripping the gfci but unfortunately the company I work for doesn?t own a megger or a AC leakage clamp meter. And the dental office isn?t to happy because they say it cost about 5 grand for a new sterilizer... not sure what it would cost to repair it if possible.

All you need is a regular clamp meter around the ungrounded and grounded at the same time. It should be zero. Check wiring compartment in sterilizer with meter and check for possible N-G continuity.

 

[jeremysterling]

We are under the 08 code. We narrowed it down to one machine tripping the gfci but unfortunately the company I work for doesn’t own a megger or a AC leakage clamp meter. And the dental office isn’t to happy because they say it cost about 5 grand for a new sterilizer... not sure what it would cost to repair it if possible.

Hard wire it with a switch, no GFCI required.

ETA: only after checking out the sterilizer for unsafe condition!

 

[busman]

All you need is a regular clamp meter around the ungrounded and grounded at the same time. It should be zero. Check wiring compartment in sterilizer with meter and check for possible N-G continuity.

Most regular AC clamp meters are not sensitive enough to detect current leakage on the order of 10 mA. That's why a leakage clamp is such a vital tool. There are models available for about $150.

Mark

 

[iwire]

Hard wire it with a switch, no GFCI required.

That is not always a code compliant solution.

 

[KansasSparky]

Would cutting the cord and hardwirng the machine void its UL listing?

 

[mcclary's electrical]

Would cutting the cord and hardwirng the machine void its UL listing?

yes.......

 

[ActionDave]

I went on a service call with my supervisor to a dental office. They have two sterilizers plugged into the same circuit along with some other small machines, the problem is that they are tripping the gfci that they are plugged into. We put a clamp meter on the circuit and it is pulling 22 amps. We separated the circuit and added another gfci because my supervisor thought that the gfci was acting as a breaker and tripping. We got called out again because they are still tripping but only one of the sterilizers is tripping the gfci?s. Both are brand new gfci?s and the sterilizers pull 9 amps a piece. My thought is that the sterilizer is leaking current which is what is tripping the gfci. Is there anyway to test the machine to check this? And we can't put in a regular duplex because it is within 6 ft of a sink.

Nobody jumped on this. You guys are getting all soft and new agey.

 

[kwired]

We are under the 08 code. We narrowed it down to one machine tripping the gfci but unfortunately the company I work for doesn?t own a megger or a AC leakage clamp meter. And the dental office isn?t to happy because they say it cost about 5 grand for a new sterilizer... not sure what it would cost to repair it if possible.

It may need serviced or replaced soon anyway, the GFCI tripping may be early warning of total failure of a component like a heating element or something like that.

As far as them not being to happy, I'm not particularly happy about how much dental work costs when they tell me what I need to have done