PSA: Put a Surge Protector in your Main Electrical Panel

[Bainbridge]

ZZZZOTT!!!

So some of you may know that it's been stormy these last couple weeks up here in the Pacific Northwest. Lost power a couple times, afternoon or two of brown-outs. Somewhere in there a power surge took out the middle leg of our 3-phase on our glycol chiller. This is the unit's main on/off where the 208 3-phase goes in. Compressor kept running for a week or two in single phase, but the additional (nearly doubled) amp draw eventually cooked the contactors on the compressor control, which is when we noticed the problem after it started tripping its breakers. The glycol system went down for a day before we could repair it. Lost a batch of IIPA that shot to 83 degrees overnight and is now going on as a 'Taproom Special' while we race to rebrew it. The surge also apparently addled the brain of the brand new VDF on the recirc pump, which now needs to be replaced as well.

Didn't know anything about installing a 'whole house' panel-mount type surge protector on our panel when we set up, and the electricians didn't mention one. Few hundred bucks might have saved us several thousand in insurance claims. Argh.

[jebzter]

Just to add to the surge protector idea, our glycol chiller has a device in it that will not allow the contactors to pull in unless all three phases are present and in the correct order to prevent the compressor from running backwards. It is really nice in the event you loose a phase.

[gitchegumee]

I second Jebzter!

This is common on large equipment. Saved us a few chillers in the past when (can you believe this), the municipal power source was restored after an outage with phases reshuffled! Although this clever device saved us the chillers by locking them out, we first noticed something wrong when our malt mill wouldn't crush malt because it was running backwards! Every time I think I've seen everything.......

[Bainbridge]

This is common on large equipment. Saved us a few chillers in the past when (can you believe this), the municipal power source was restored after an outage with phases reshuffled! Although this clever device saved us the chillers by locking them out, we first noticed something wrong when our malt mill wouldn't crush malt because it was running backwards! Every time I think I've seen everything.......

Wow, now that's a good one!

[rdcpro]

Lost phase protection is a really good idea, as a 3 phase wye-wye connected transformer has a primary fuse on each phase, and I've seen them go before, dropping a phase. A delta-delta connected transformer can lose a phase and keep going, albeit at 53% of rating, so loss of a phase wouldn't necessary be harmful. In fact, many 240 volt 3 phase systems only use two transformers in the first place, unless it's a critical application like a pump station. But usually this is only found in rural areas. It's an uncommon situation for an industrial building; they're almost always wye connected, because you need a neutral, and this lets you run 120v loads from all three phases. A 240 volt "open delta" system has a third leg (the "b" phase, called the "stinger") that is about 208 volts to neutral.

Anyway, I'm not sure the surge protector would have helped in this case--it would have to be enough to trip the main panel feeder breaker. A surge protector works by shunting when the voltage rises above some predetermined point, which should, in theory, trip the feeder, except for short term transients within the power limits of the device. A lightning arrester work in a similar way, but is designed to shut a lot of current compared to the typical surge protector. I repaired a panel some years ago that had a lighting arrester, and a nearby strike literally blew the arrester to tiny pieces (leaving a huge black scorch on the wall). It also blew the panel cover across the room, and blew out every knockout in the panel. BUT, it saved several racks of equipment.

But if you have a breaker with a remote trip circuit, or can install a large contactor, a very simple phase detection device can alert you by tripping the mains. You'll still lose power, and possibly the IIPA, but at least you'll know about it! If nothing else, lost phase detection connected to your building alarm system might be a possibility.

I'm very surprised your chiller survived with as little damage as it did...in fact, if it was truly a lost phase, the compressor would likely not start, and you'd be looking at a rewind of the motor.

Couple questions:
1. Was that wired with aluminum wire, or copper? I noticed anti-oxidant grease on the connections, which is done when using aluminum (though sometimes electricians will use it on copper as well, especially near the water as you are).
2. Did you lose the third phase to the entire building, or just the chiller?

The reason I ask is that I've seen the exact same situation in your photo on equipment due to a hot connection, usually caused by a loose connection, or the use of aluminum wiring. Aluminum needs to be properly torqued, and rechecked periodically on larger loads. This type of failure can take a long time to develop, and sometimes results in a fire. But its not related to a power surge, and a phase loss detector would not have helped unless it was connected downstream of that contactor.

Regards,
Mike Sharp

[TGTimm]

In the even-more remote far NE Oregon, we've battled phase loss for years without knowing what was killing our motors and compressors. Finally one day I was in the shop when all pumps stopped pumping and started quivering in place. I immediately hit the main breakers in our boxes and found that the high leg of our Delta wiring was out.

The power company still refused to take responsibility for our numerous losses over the years.

I've since installed "motor savers", phase loss shut-outs, in all our equipment. There are several varieties of these out there, some simply shut the equipment down until all phases are restored and in proper balance, others have many more functions, programibility, and, really handy, fault memory so you can find out what exactly went wrong and work with the power company to prevent it happening in the future (hopefully).

I installed one of the latter in a convenient place to monitor it, and the cheap ones in every other piece of 3-phase equipment. Since then, of course, we haven't had any problems, but when we do, we're covered.

Most new equipment purchases can be specc'd to include 3-phase motor protection. It's cheap insurance.

Whole-house protection--either surge or phase detection--is prohibitively expensive. Surge protection/UPS on all electronic controls/systems and motor savers on all 3-phase, and you're good to weather the little glitches. Beyond that, a back-up generator is the next step.

[TGTimm]

Ironically, I went to start our main HL pump today--one day after posting the above--and it immediately stopped running. I opened the motor control box, and the motor saver had the phase-fault light lit. I checked the voltage (after checking the breaker, which had not blown), and one leg was at 9.8 VAC! One leg of the breaker had burned out, with no visible damage. Had I not installed the motor saver, I'd be replacing a 7.5 hp 3-phase motor on Monday!

[gitchegumee]

Exactly Timm....

Feels good to have done it right and be vindicated for protection. Seems like most motor problems happen on startup with high inrush currents. You have a source for combination soft-start/phase direction/phase dropout protection?

[TGTimm]

Philip--the phase protectors I'm using are from ICM Controls--I think I bought them from Supplyhouse, but not sure. The fancy, programable, recording unit was ~$125, the cheapo just-phase monitoring/protection ones were ~$25. Both protect against phase reversal, loss, and imbalance. The fancy one can also monitor motor health by monitoring draw/phase return on each winding.

We use these in combination with the motor starters--the "motor savers" go in series with the various controls to the coils of the main definite-purpose contactors. There may be units that incorporate both, but as I was adding these to existing equipment this worked quite well.

When installing these. it's usually a bit of trial-and-error to get the phases right on the motor savers--with our Delta service, this means switching the low legs, then checking for motor rotation and correcting if needed.

[Bainbridge]

Couple questions:
1. Was that wired with aluminum wire, or copper? I noticed anti-oxidant grease on the connections, which is done when using aluminum (though sometimes electricians will use it on copper as well, especially near the water as you are).
2. Did you lose the third phase to the entire building, or just the chiller?

The reason I ask is that I've seen the exact same situation in your photo on equipment due to a hot connection, usually caused by a loose connection, or the use of aluminum wiring. Aluminum needs to be properly torqued, and rechecked periodically on larger loads. This type of failure can take a long time to develop, and sometimes results in a fire. But its not related to a power surge, and a phase loss detector would not have helped unless it was connected downstream of that contactor.

Regards,
Mike Sharp

Thanks Mike. Huh, maybe that was what happened and it just coincided with the power fluctuations? Aluminum wires. Installed three and a half years ago. Think I re-torqued them once, maybe two or three years ago. Wire insulation was melted up a good half inch from the switch. Didn't lose any phases other than the one through the switch (the really burned one lost contact all the way through, voltage going in was just fine.) Hmm. Well, still a phase loss detector sounds like a good idea anyhow.

[rdcpro]

Thanks Mike. Huh, maybe that was what happened and it just coincided with the power fluctuations? Aluminum wires. Installed three and a half years ago. Think I re-torqued them once, maybe two or three years ago. Wire insulation was melted up a good half inch from the switch. Didn't lose any phases other than the one through the switch (the really burned one lost contact all the way through, voltage going in was just fine.) Hmm. Well, still a phase loss detector sounds like a good idea anyhow.

It may be the power fluctuations stressed it out, causing the failure to occur earlier, but yeah what you describe with the burned insulation is a classic aluminum hot connection. It takes a long time to initiate but once the damage is done, it gets progressively worse at a faster and faster pace. So some excess starting current, or brownouts and such could easily have pushed it over the edge. But you were going to have a failure eventually, regardless.

With aluminum wiring, you should probably check heavier loads periodically with an IR non contact thermometer, although you can usually see this damage initiate. Any connections that look significantly hotter than the other two on the motor circuit should be re-made. When re-torquing, pay attention to the "feel" of it. If you feel like there's sand in the connection when tightening, you probably already have surface burning inside, so remove the wiring, clean it with a wire brush (but careful not to nick Aluminum!), regrease and put it back together. If there is too much damage, cut it off and strip a new end. I've always preferred the gray NOALOX, rather than the clearish green grease, but it gets everywhere and the graphite stains everything.

The motor savers that Timm is talking about can be connected to the load (motor) side of the wiring, and they will alert you to the problem before it turns into a fire. Cheap insurance, for sure. However, if you add the motor saver, it's probably not a good idea to double-up the connection, meaning don't try to put both the load wire and the motor saver wire in the same clamp, especially when one of the conductors is aluminum. It's only the bigger loads you usually have to worry about; air compressor, chiller, any large pumps...Smaller loads you can't use aluminum on anyway, though undersized relays and contactors may still burn their contacts.

When I used to do this stuff all the time at some of the more remote wineries around San Luis Obispo, I fell in love with Euro controls, because unlike a lot of NEMA contactors, all the parts for each phase were identical, and you could almost always disassemble the contactor and swap out the burned contact with another one, or else dress it up temporarily. Usually one phase is going out first, and swapping with the contact that's in the best condition can extend the service life a few days. That way the crush can go on. I never tossed any bad controls--they're filled with highly valuable spares!

Now that I look again at your photo, I guess that's a rotary disconnect switch, and not a contactor...but the principles are the same.


Regards,
Mike Sharp

[TGTimm]

You have a source for combination soft-start/phase direction/phase dropout protection?

I forgot to mention--most if not all VFDs will not allow an output (fault alert) with phase imbalance, and totally correct phase direction--try switching two of the input wires on a VFD and you'll see the motor still turns the same direction.

[jebzter]

I forgot to mention--most if not all VFDs will not allow an output (fault alert) with phase imbalance, and totally correct phase direction--try switching two of the input wires on a VFD and you'll see the motor still turns the same direction.

Depending on the VFD, they will still work with one phase out. Many are able to convert single phase to 3 phase, with an increased load on the two lines coming in. I know ours has worked this way, even if a phase is out we still get full power on the VFD output.

[TGTimm]

Good point--I'd forgotten that some VFDs can be used to convert single-phase to 3-phase. The units I've seen that do this are usually smaller than most of our VFDs, I think mostly topping out around 1 1/2 hp.