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Clean Water Systems – Issues, Opportunities, Information
Surge Protection
Our team from the San Gabriel Presbytery recently returned from doing two installations in the Huanta, Peru area. Everything went well while we were there, but just a few days after our departure a thunder storm blew out one of our UV control units. We were fortunate to be able to get a replacement unit back to our partners and have it installed in about 10 days. What we asked them to do was to add a surge protector to the system, and we asked our other partner church to retrofit theirs with a surge protector as well. The surge protector is a minor expense compared to replacing the UV unit (especially since the UV units are not readily available across Peru and shipping them there is not feasible for a variety of reasons). We are adding surge protectors as a standard part for future installations and hope that other teams might consider doing so as well.
Rob:
Thanks for sharing your experience with your installations in Peru. LWW has had a few components on the board get “fried” with a lightning strike.
Do you recall the type and manufacturer of the surge protector or was it a generic one that is supplied with many power strips? Please let us know which one you select for future installations so that we can consider adding it to the Standard Clean Water System.
Ralph
Ralph and all the rest of you:
We don’t know what sort of surge protectors they chose to install (if in fact they have done so yet), but on top of the surge issue the same site had their first lamp blow out in just about 4 months. Apparently they have issues with voltage irregularity. We have been pondering a number of solutions but haven’t arrived at the one we think is quite right yet. One possibility is an interruptible power supply that would give them battery back-up in case of an outage and smooth out their electricity supply to a pure sine wave to the pump and sanitizer, but those are expensive if sized to do even one cycle of water purification and require periodic battery replacement (further costs). Another option is to add a capacitor to the breaker box which would regulate the power supply, but my personal experience is that they can have a relatively short life if there are large swings in voltage coming through the system (I used to have a 120v water pump that had one and needed to be replaced every year or two – but if they are readily available and relatively affordable in Peru might just work). We are talking to all the electricians and engineers we can find for ideas, but no good ones yet. Do any of you have any thoughts? We are just a bit less than a month off from our next install and would like to solve this problem.
But the simple solution in the mean-time is to add a decent surge protector for the electrical equipment while it is in use and shut off the electrical supply at the breaker (not simply unplug) when the system is not in use. The breaker should stand up to more cycles than plugging in and unplugging the system.
Blessings, Rob
Rob: Here’s a response from one of electrical guys with LWW and SUTS experience.
But first a few questions. What is the nature of this installation? Is it on the grid or a generator? I am assuming it is on the grid. Do we know if other electrical equipment in the area have problems? Is this a rural or urban location? I am assuming rural. Is this a 120 VAC installation or 220 VAC since Peru was mentioned?
Voltage surges can occur from several causes. Being at the end of a long rural service line and a heavy load somewhere nearby is turned on (or off) can cause a surge. Poor regulation at the generating station can put surges on the line. And lightning can certainly cause surges.
Electrical equipment reacts to surges differently. First let’s consider devices with motors like pumps. A short surge, unless it is a really high over voltage like a lightning strike, usually won’t bother a motor, with one exception and that is if the motor has a starting and/or run capacitor. Voltage spikes will take those capacitors out and the coils in the motor will be just fine. In general motors are more bothered by long periods of over or under voltage which cause them to overheat and ruin the coils.
For electronic type equipment like ballasts, lamps, and even light bulbs, short surges can be catastrophic. These devices are the ones most helped by some sort of surge protection device. and they are the devices that generally use less energy, so an arrangement to just protect them might be less expensive.
So what to do?
First do a survey of the area and see if others are having power problems. Like we do a community survey on water problems to see if disease is prevalent. Same idea for power. If you are putting in a new pump, try to use one without a capacitor. They aren’t quite as efficient, but can stand more trash in the electrical supply. Make sure you have a good local ground and that all the water board equipment is properly bonded and grounded. If you are on a long rural distribution line, see if a lightning arrestor can be installed on the service. I think that should be left up to the local utility/power company and I know there might be a fat chance of that ever happening.
Then as has been suggested use the ultimate lightning arrestor and that is arrange all the power to the water board go through a heavy duty plug 3-prong and UNPLUG the system when not in use or in the event of a storm nearby. I disagree with using the breaker to isolate the system as the ground connection will still be intact and if the community ground is not good or far away strange things can happen in the ground connections. And although we all do it, breakers generally DON’T LIKE being used as switches. They want to be turned on and left alone.The way to make the arrangement for a easy unplug system would be to bring in the power to a breaker box for the total system. Make a ground connection to a good ground rod from the breaker box. Go out of the box to a heavy duty 3-prong receptacle. Then take some #12 with Ground service cord (the plug end of a heavy duty extension cord would be fine) and run to the water board. American electrical code says it should be more that six feet from the breaker box to any conducting surface on the water board. So during a storm the water board would be unplugged and would be electrically “floating” and it would not suffer any surges. Same would apply to other times when the board is not in use. All of this generally applies to situations where the surges are mostly due to lightning. It would not be as effective for other sources of surges such as poor regulation as the timing of those surges can not be forecast very well. You can see, and hear, the storm approaching.
The use of an uninterrupible power supply to run the pump would generally not be cost effective. You could buy several pumps for the cost of the UPS, I bet. And the UPS would have batteries to maintain, etc. Surge protectors for the ballasts (UV or O3) would not be a bad idea.
Since your trip is only about a month off the following suggestion wouldn’t help, but you might consider it for the future. If the power situation remains really bad, how about going to solar power? A stand alone, non grid connected system as presented by SUTS would clean up all the problems you mention. Several of the systems that have gone into Haiti already were retrofits for existing locations that had generators or bad grid power. Something to think about.
Hope these comments are helpful. If the nature and source of the surges in power can be better determined, more specific suggestions might be possible. Like we can’t fix the water until we do a water test and community survey, we can’t really fix the power until we know what’s wrong with it.
I hope some of the other “electrical guys” chime in.
Keep clean (and when necessary, solar powered) water flowing.
Dave Howell
Rob – Here’s additional advice from Tom Pierson, one of our CWU ROS instructors.
One practice I’ve used for the past few years is that as soon as I arrive on site for an install I’ve hooked up my digital voltmeter and left it attached for the total installation. My team and myself continually look at the meter during the install to identify voltage variations at certain times of day at the site. My meter also has a high/low memory feature that I can check to identify spikes even though it could not identify the time they occurred.
At one site that was at the end of the grid, because the street was extended to accommodate the new church, we kept getting intermittent voltage drops to 92 volts. In a walk up the road we found a mom &pop mini furniture factory with an old table saw and planner. We discovered that the planner was causing the drop. The church water committee coordinated the water plant operation with the planner operation and solved the problem.
More feedback from Rob:
1. The system where we had our lamp burn out was not a rural site, but a fairly removed small town. We honestly don’t know what the electrical problems are there, but something clearly caused the first UV lamp to fail prematurely. I know my earlier post indicated that it died after just 4 months, but really it was worse than that. Shortly after we had the UV controller replaced (about 2 weeks after installation) their water supply was cut off in the course of some road maintenance and they went about 2 months without being able to run the system. So, the short story is that their lamp really lasted only about 2 months. Maybe it was just a bad bulb and there is nothing wrong with their electric supply, but we just don’t know. I very much like the idea of putting a digital volt meter with memory capacity on the system when we return there next month so we can do some analysis while we go through our follow-up visit with them, and also at the site of new installation. Anyone willing to suggest a brand and model for us to purchase?
2. Yes, being Peru the electricity is nominally 240v. But what I haven’t seen in Peru is a 3-prong outlet. They use round 2-prong fixtures. Yes, we grounded the systems with grounding rods, but someone else on our team would have to answer the question of how that grounding would work with 2-prong outlets. It is beyond my knowledge. As far as the pumps go we haven’t had a problem yet, just the UV part of the system (oh, and I probably should have been clearer in my earlier reference to a capacitor on a water pump – that was at my cottage in Canada that ran off a generator – it was the fact that the generator was just marginally large enough to run the pump that caused voltage fluctuations leading to capacitor failures). So the question of a capacitor was much more about regulating the UV system and not the pump.
3. Our immediate first solution will be to make sure that surge protection is added (honestly, I don’t know if our operating partners have actually put those in yet). Second, we will take the recommendation to heart and not use the breaker as a switch. We will just unplug from the surge protector and figure on replacing it or the plugs when they go bad. Fortunately we have an electrician there who can advise us about the best procedure for connecting the surge protector to the power source and ensuring that a proper ground is maintained using the plugs that are available there.
4. We will not be implementing a UPS – the observation is correct that they would not be cost effective – especially as far as the pumps go. Were we to start having failures with them we could buy 4 or 5 pumps for the price of one UPS.
5. As for solar power, that will be a great question as we move forward. We may be moving on to locations where solar is an imperative and not merely an option. But for these first 3 systems we really have to stay on the local power grid.
Thank you all so very much for providing feedback,
More comments
Just a couple of thoughts regarding Rob’s list below:
1. Given that they had no water for a couple of months, I cannot shake the suspicion that they left the system, or at least the UV lamp, powered during that period. Running for two months with no water flow would probably burn out the lamp, in fact the best evidence so far that they did NOT leave it on is that the lamp lasted two months after water returned. But I think we must ask the question.
3. Can we not add a switch between the breaker and the UV light? Does the power line have to be physically disconnected to protect from lightning and power surges? We certainly don’t bother with that here in California…just turn the circuit off at the wall switch.
More from Dave Howell
Thanks for the description of the situation at the installation site. Use of Tom’s idea with the voltmeter with memory sounds like a good idea. I really can’t guess the cause of the early failure of the bulb. Could have just been a bad bulb. How long have the other bulbs been running now? Many months? If so I would lean toward a bad bulb.
About two wire systems. Way back in the US we had a two wire system also. In fact I have to deal with it all the time in my Church as part of the building is 100 years old. The wiring is not that old, but a good bit precedes the changeover to our present three wire system. In a two wire system, one wire is the “hot” wire and the other wire is the common or return and it is also connected to ground. So if the plugs and receptacles are wired properly and are polarized, equipment that is plugged in gets power and is also grounded. That’s some big “if’s”. The ground ( or common) wire is CURRENT CARRYING which our modern three-wire system does not allow. But that’s how it was done here in the US for about eighty years from the advent of AC wiring in buildings to the introduction of the three wire system sometime around the late 1950′s. The house I now live in was built in 1955 and had a two-wire system and my Dad who had it built was an Electrical Engineer so I am sure it was built to the Code of the time. I have had the house rewired to three wire configuration.
So can you change a two wire system to a local three wire installation? Maybe. In theory if you can determine the “hot” wire in your supply and also determine that the common really is at ground, you can set up a small breaker box, run the hot to the supply side of the breakers as normal, run the supply common to the “Neutral ” bus as we call it and bond the Neutral bus to the ground bus and run a ground wire to a ground rod. Then downstream wire everything on a three wire system as we would here in the US. The only kink in this is whether the common is really at ground. If you can follow the service wires back upstream to the transformer that serves the area and determine that the common is really grounded at that point, you should be good to establish your local three wire system as described above. A local electrician may know where these connections are. If the common is really way off ground, then an isolation transformer might be required, but that is beyond this discussion right now.
My experience in doing wiring in Peru was that all the components were from the UK ( three wire plugs and receptacles) and all the wires were the same color. Yes there were three, but they were all blue! And in conduit between boxes! The UK code does have a two prong polarized plug with round prongs as well as three wire plugs with round plugs. I would use the three wire UK plugs if you can find them. There were US type plugs floating around as well, so I guess you could use them, if you need to. Talk to your local electrician and see what he thinks.
Notice in the above discussion for the two wire system, I did not use the term “neutral” in the discussion of the two wire system. In Peru (and also the UK) the 240 volt system is really 240 volts between the common and the hot wire. In the US system you get 240 volts between two “hot” wires, each of which is only 120 volts away from the neutral which is also called the common.
I am accused of being a “belt and suspenders guy.” I am at the end of a rural electric distribution line. When the thunder storm (Why do they call it that? It’s the lightning that does the damage.) rolls in, I run around the house unplugging all electronic equipment. Computer and peripherals are on one plug strip to make that easy. Also TV, Stereo, microwave, and even the washing machine which is one of the new ones that has electronics to make a DC motor run both ways instead of the old wig-wag washers used to have. My well, which is now just used for raw water, has a submersible pump in it that is getting close to 40 years old. It is on a plug also. Is this necessary? Well the phone company has had to come change out stuff several times. I haven’t lost anything. In town I think the lightning can find other, more attractive targets. Out here I’m it, so I unplug. Not to be a smart Alec, in California you have a good three wire system in your house, you have a good ground for your house, there is a transformer serving just you or maybe you and a couple of neighbors, not half the neighborhood, and the power company has a lot of protection equipment on the distribution system. So you can probably can just turn the switch off at the wall and everything will be OK. In Peru you wouldn’t have all that infrastructure.
I hope this information is useful to you. If you already know and understand all this, fine. It helps me to go through this thought process every once in a while, so the practice does me good.
As far as solar power is concerned, I always say the first choice is a power grid if it is at all reliable. Much simpler. Generators get more questionable, with many variables and safety concerns. Then solar if you have to. But solar will do the job.