Troubles on Simplex 4005

Greetings from Maine. My name is Chip Gray, I’m a licenced aircraft mechanic that owns and operate a nice hotel in Freeport, Maine. I’ve got a simplex 4005 that has periodic ground fault troubles . Simplex seems to be unable to troubleshoot the problem, and their sales staff is hot to have me buy a new system. (pretty tough timing for us)

I’ve read some of the posts on this site and can recognize expertise when I see it… so, I’d entertain giving a nice weekend stay and some food to one of you experts if you’d come fix my system and save me some money!

Check out our place at


Unless the ground fault is internal to the panel, which it probably isn’t, the panel does not need to be replaced. Simplex tech’s often don’t trace ground faults (at least not here in my area). Call another service company that is not Simplex and see if they can handle the situation for you. A ground fault is a short to ground at any point in the system, could be on a device or a wire somewhere, but a meter, time, and knowledge is required to handle it.

Another point to consider, when the ground fault troubles occur, make a note of which zones experience the fault, the time of day, the weather, and any other unusual happenings when the trouble occurred. I once had a situation where a Fire Lite MS9050 would go into ground fault trouble intermittently, and the staff couldn’t tell me when it started. It finally happened to go into trouble on a day that I was there, and I found a slight leak in an RTU that let a small drip into a duct detector. The fault only occurred when it rained heavily. You may be able to make similar observations (only happens when an RTU is working hard on a hot day, only happens during a rainstorm, only happens when there’s heavy demand for water, etc), that might point to the possible location of your fault. This type of information can be very helpful to service techs, especially if they’ve never set foot in the building before.

I totally agree with AlmightyZach, unless there is an internal ground fault, the panel itself is most definitely fine.

I agree with both of them :point_up_2:. Sometimes you get lucky and can find where water has gotten into an exterior device, but most of the time you have to be there when the ground fault is active to find it. Easy to verify if the panel is clear by disconnecting every circuit including the batteries and phone lines and verify the ground clears. If the panel and rest of the system are sound besides that, I say find someone else local to troubleshoot the ground fault. Wish I could make the trip up there to help.