Michael - California, USA
Micro-Mark MicroLux 7x16
LMS 3990 Hi-Torque Mill
-----Original Message-----
From: GrizHFMinimill@yahoogroups.com [mailto:GrizHFMinimill@yahoogroups.com]
Sent: Friday, March 04, 2016 3:15 PM
To: GrizHFMinimill@yahoogroups.com
Subject: Re: [GrizHFMinimill] Re: tripping circuit breakers
Hi everyone and again thanks for all the suggestions. Hope this is not too long.
Well the electrician left after two and a half hours investigating the breaker tripping problem. There is still no real solution in fact it just might be worse.
To recap the problem, my mini mill is on a basement circuit. It is plugged into an outlet that is the only thing on that twenty amp standard breaker. No other outlets or lights are on that circuit. When I start the mill by turning on the variable speed knob it will sometimes trip the breakers for the kitchen. Other times things will be ok for a little while then the kitchen breakers trip. The mill continues to run. This happens also if the mill is in operation and the coffee pot or the toaster are turned on. It does not seem to happen if the microwave is turned on. It sometimes happens when the refrigerator comes on but not always. The 20 amp circuit for the mill or any of the other never trip, only the kitchen circuits.
There are two 20 amp arc fault protected circuits to the kitchen. Code for our location. These are tied together, two pole I think that is called. One is to the four duplex outlets near the sink. The other is to the stove and the refrigerator on the opposite wall. One sink side outlet has the microwave and the toaster plugged into it almost all the time. It is a GFI outlet and protects it and an outlet farther to the left that powers our caption phone. The GFI outlet to the right of the sink has the coffee maker and coffee grinder, it also protects an adjoining wall outlet which is almost never used. I ran an extension cord from the laundry to the mill and it did not seem to trip any breakers. However that is not a viable long term solution and swambo “does not want that thing in the laundry” anyway.
I printed off the comments that have been received so far and I’m not sure he understood “ground Loop” concept. I don’t think I do completely either in this situation. He did do a lot of testing and moved the kitchen common (white wire) which had been connected to the bus bar next to the mill white wire to an open spot further down. Most of the grounding is through the metal conduit and one BX to the panel case and from there to the street side of the water meter. The only exceptions are two romex circuits with the third wire grounded to the case. He installed new arc fault breakers for the kitchen. None of this made any difference.
His only other suggestion was to swap out the arc fault breakers with standard breakers which would not be code. I stayed with the arc fault breakers, so as not to do anything that might void my homeowners insurance. The only difference now is that sometimes only the sink side trips and not the stove and fridge side. But sometimes both still trip. So we are still at square one.
I hope this is all clear as I make no claim to be an electrician and might not use all the correct terminology.
I have included a link to photobucket with photos of the breaker panel, the panel interior, and the label on the inside of the door if any of that would offer any clues. The set of breakers that trip are the third down on the left side. The circuit with the mill is the top red one on the right side tagged Freezer. Also in that album is a photo of an Ibbotson saw medallion ca. 1890’s that we found in a cave in southern Minnesota. It shows king George and the dragon probably in celebrations of Queen Victoria’s anniversary.
http://s631.photobucket.com/user/dennyom/library/
There are also a few photos of my shop and a leather mallet that I designed and built a few years back, if anyone is interested.
http://s631.photobucket.com/user/dennyom/library/Leather%20Mallet
http://s631.photobucket.com/user/dennyom/library/bench
Dennis
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