I hope someone can help us on our GFCI problem.

I have two GFCI with separate circuit breaker. On the 1st GFCI I have 2 pond pumps connected to it. The pumps have been working fine without tripping the GFCI for 2 years. About a month ago the 1st GFCI tripped and after some testing I found out that I can only connect one of the pumps at a time. Connecting both pumps will trip the 1st GFCI.

Initially I thought the problem was w/ the pumps but when I connect both pumps to the 2nd GFCI it worked fine without tripping it. I also replaced the 1st GFCI with a new one but the problem still occurs.

Any suggestion on what can cause this problem. There are no other appliances connected to either GFCI. Both GFCI are located indoor.

Thanks in advance for the help.

The second GFI may be defective and not detecting a ground fault that the first GFI is detecting. Does it trip when the test button is pressed?

Are these GFI next to each other? Are both fed with the input connected to the LINE of the GFI? Just trying to get more info to figure this out.I go with checking the second GFI.

The second GFI may be defective and not detecting a ground fault that the first GFI is detecting. Does it trip when the test button is pressed?

Are these GFI next to each other? Are both fed with the input connected to the LINE of the GFI? Just trying to get more info to figure this out.I go with checking the second GFI.

tkrussell thanks for the reply.

The 2nd GFCI does trip when the test button is pressed. These two GFCI are not next to each other. Both GFCI are also fed with the input connected to the LINE.

I also tested the pumps with other GFCI in the house and it work fine. I am running out of idea :(

What do you think that might cause the problem.

Regards.

OK now you got me, this is definitely a weird situation. What you have is a good comparison between two apparently good working GFI receptacles that should react the same to the same load being applied.

Assuming all things being equal, each GFI should work fine. All I can think of is either one GFI is more sensitve or the other is not as sensitve as the other.

Here are a few ideas to try:

When you try one and then the other device, is the cord length the same, or do you need to use a cord to reach one and not the other?

Is is possible to use one GFI to protect the other receptacle location, and change out the second GFI to a standard outlet?

Can you change out both GFI to two new of the identical type, brand, etc, to be sure there is not some sort of device problem?

Again, you got me on this one, seems that both should be fine.