Troubleshooting Flickering Power Supply

Poor quality power might be a site maintenance issue. April 2, 2013

Where I reside (in the middle of nowhere) the power flickers most of the time, bad weather or good weather. I'm looking for suggestions for surge protection and a backup power supply for a small CNC router. Nothing fancy just functional.

Forum Responses
(CNC Forum)
From contributor G:
What kind of power does it require - 120, 208, 220, 440 vac? Single or three phase? What about current requirements?

From the original questioner:
The CNC runs 220v, 30a single phase with a 30a 250v plug. The left prong is horizontal, if it matters.

From contributor S:
Flickers, or are they uncontrollable surges and spikes? If it’s the latter then it may be that you need to try is an isolation transformer to smooth out the wave.

From the original questioner:
Flickers to full brief outages then right back on. Only the best in PA! Guess we're lucky when the lights are on! So with all of the above I might go a month or two with nothing then several days in a row with interruptions , then back to nothing.

From contributor D:
In that case I would start looking for a surplus military 3 phase generator. They’re on small trailers. Keep your eyes open they are around. Just use it when you’re running you CNC or if the power goes out for any length of time. Or get a large single phase generator that works for you.

From contributor C:
Hire an electrician before anything else and make sure all the lugs are tight at the meter base and all your connections are forward. That is number one. Then look at an isolation transformer.

From contributor F:
I had a situation where battery backups were kicking in for milliseconds, lights were flickering and I couldn't figure out the cause. It turned out to be the connection from the cable from the meter base to where it tied into the main breaker on the service panel.

A year later same deal, but in an out building serviced by the main panel. Lights flickered, battery backup on a unit kept kicking in and out and it turned out to be the lugs that tied the main service to the panel in the out building. I think an issue that hasn't been asked is how old is the service path to your problem? If it's only a year or two old, probably what I've said doesn't relate. If it's a decade or more, then you should confirm the integrity of the electrical path from where the transformer meets the meter base and beyond.

From the original questioner:
Thank you - these seem to be what I had in mind and possibly a panel mounted suppressor. We'll see what the electrician has to say.