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What sort of hobby would we have without electricity? No pumps, lights, heaters, & other myriad utility-smile-generating devices? No fun, and lots of work.
Alas, there are some folks who get along without fuel bills; and indoor plumbing! But most of us mere mortals are hooked on modern conveniences... Ponds and other large outdoor water effects pose added dangers compared with indoor appliances. Their electrics and controllers being able to fall into the system, often with much larger amperages & sometimes voltages, are exposed to water, more abrasives, overall extra hazardous influences (let's hope) than those inside the home.
So what's the big deal? Well, akin to gasoline use, & the opposite of familiarity, electrical use does not breed contempt, but complacency. We're so used to using and getting away with abusing it we've become oblivious to electricity's dangers. EMF (electromotive force) is a powerful energy source, and one to be reckoned with. Follow along with this dissertation... it may save your fishes and even your life.
Each year I read of reported accidents involving aquaristics; traumas from lifting poorly, slipping or having structure fall on people, cuts and gashes from rockwork, pokes and envenomization from venomous critters & & &. Most of these are non-fatal.
Invariably, every year there are cases of electrical shocking, and no doubt orders of magnitude more that go un-reported; & then there are a few electrocutions; yes deaths. Though mortality from electrical shock associated with aquatic gardens is rare, it can and does happen.
This makes imminent sense given all the factors listed in the introduction above regarding outside water effects. Let's list the major sources of these shocking situations and how to avoid them.
The biggest offendi due to typically higher amperage than other electrical devices used around ornamental water features. Maybe this is 'that' opportune moment to launch into highlights of High School level understanding of Physics? Okay! Basically; consider that some number (Coulomb's) of electrons "passing" a given point on a conductor (like a wire) every second we'll define as an amp (or ampere). The amount of energy or capacity to do work (measured in various ways) per this batch (number) of electrons we measure in volts.
You can have a situation with either a whole lot of electrons (amps) with very little average energy (volts) or relatively few electrons (amps) with lots of energy (volts) and not get badly shocked. Problems arise when you get mucho electrons with high average energy together at the same time. The measure of this product, volts & amps is described in the following way: volts (the average energy) times amps (the number of Coulomb's number of electrons per second equals Watts, or
Coulomb's Energy Energy
--------- X -------- = -------- (Energy per Second)
Second Coulomb Second
Amperes Times Voltage equals Wattage
Simple, huh? Let's look at some real life examples- How bout a small vibrator-type air pump? Yep, it's plugged into a 110-120 volt outlet, and it draws or consumes a few (let's say thirty) milli-amps (that is, thousandths of an ampere) to power that burping clam and frog on a frog on a log. Sheesh. Multiply that all out as 110 volts times .03 amp and we have 3 watts per hour. At let's say ten cents a kilowatt (1000 watts) per hour, you can run that sucker for 3 watts/hour times 24 hours/day times @30 days/month times 10 cents/kilowatt hour times one kilowatt/1000 watts equals 21.6 cents per month.
Let's look at a typical small pond recirculating pump; a 1/6 horsepower Duraglas Sta-rite. Now we have a 110 volt motor drawing a nominal 3.7 amps; about 400 watts. This amount of 'juice' can and will kill you if your body is providing a good enough 'ground' to favor the electricity to flow through you versus the intended circuit. The service power is even greater (usually the voltage and fifteen or twenty amps) This you want to avoid; and there's a couple of ways to do it.
A) Properly wiring the pump motor (with a bonding wire, equipment ground).
B) Avoiding electrical shorting.
More about all these below.
You've heard me preach in these pages concerning what types of pumps to use, how to site and plumb them (see appropriate Sections). Try to avoid submersible centrifugal pumps (please)! Except for the low head and volume inductive (magnetic) drive types (like powerheads) these are dangerous, more expensive to operate, don't last and are easily avoidable in place of external pumps.
Must be designed, engineered, constructed and installed for the intended purpose. Underwater light fixtures, junction boxes, controllers and other gear is expensive... and for good reason. They are carefully made and tested to perform the demanding job at hand. For biological systems I implore you, use only external lighting. You'll get more light, cheaper light and fixtures, less chance of shocking you and your livestock; and besides, underwater lighting seems to make fish/es real skittish. Enough written?
Re lighting and pumps: there is such a thing as low voltage and amperage equipment. These are operated through electronic transformers mounted outside the water but close to the device/s they serve. These items are more popular in other countries that typically utilize more than 110 volt circuitry.
U.V.s, heaters (yes, even for ponds), switches and more are also subject to wear and shorting. The same issues, warnings and safety notes apply to them as detailed next. But before we go on to connectors & cables, etc. allow me some elaboration.
Ultraviolet sterilizers require cleaning and inspection at regular service intervals. Check around compression couplers and nuts, sleeving (if present) and contact pins for corrosion, "bridging" and outright cracks and leaking. U.V.s are a common cause of electrical leakage.
Heaters: used de-icing ponds during winter and keeping them toasty at other times present the same challenges as with aquariums. They will have to be submerged per design and unplugged, cooled before immersion or removal. Keep your eyes on their cords for chafing, especially at the attachment to the heater, where they come in contact with the structure and where they plug in.
Switches and Outlets; Must be of the kind intended for outdoor use. Pay attention that irrigation is not oriented such that it sprays directly on these outlets.
Connectors and Such:
Junction boxes, conduits, wire, connectors and such are the vehicles for getting power to the electrical device. There are all kinds of help in getting these things right. I endorse Ortho and Sunset Books and other Do It Yourselfer Manuals and Guides for simple jobs. There is professional assistance galore as well to be had from a friendly neighborhood licensed waterscaper, electrician and more (see the "yellow pages" and the references in the citations below).
In general; connections must be shielded, clean, dry and waterproof. Outlets must be positioned where they cannot be reached when you're in the system. I want to mention the N.E.C. ( National Electrical Code) as the highest and best guide for minimum standards for commercial (professional) and homeowner work. Shield all strand wire and cable within conduit (generally schedule 40 PVC pipe). Make all junctions within certified J-boxes, properly mounted and filled with non-conductive potting material, and beware of intermittent underwater junctions. Most importantly, fit all 110 (and now 240) volt circuits with Ground Fault Interrupting Devices (GFIs, GFCIs). Please people, read about and use these things. They have undoubtedly saved my life and will save you from slight to serious to fatal electrical shock should the intended 'ground' fail and you (or anything else) become the alternate. Likewise don't chintz on the wire or connectors. There are some new ones that are really innovative in terms of staying together and waterproof.
When, where in doubt call in an electrician; on a consulting basis this will not be much money; and it's very well spent. If your GFI fails and won't stay re-set, & you've checked for gross errors, like dis-connected connectors, chafed or wet wiring... don't thwart it. Call in someone who can run a diagnostic for continuity and micro-voltage and amperage leaking. You'll sleep better.
Here's my suggested tools and material list for you:
1/2" & 3/4" PVC parts, pipe, connectors
Electrical Toolbox PVC
- Red MIP
Wire Nuts - Yellow Couplings
Dry Splice 90 degree Sweep
Wire Strippers 45 " "
Marking Pen Covulets
Cover Plate - Dead Close Fit Nipples
- Switch 2"
- Duplex 4"
- Outdoor Switch 6"
- Outdoor Duplex *** PVC GLUE ***
Wall Anchors Flex Conduit
Electrical Tape Conduit
Fish Tape Seal Tite
Outlet Box Conduit
Outdoor Outlet Box Connectors
GFI (Ground Fault Interrupter) EMT
Wire #12 Conduit
SLB (Short Ell Box)
Water and electricity don't mix! You've got's to be careful. I didn't even touch on (oops) the issue of minor stray and electro-magnetic effects, a new controversial "disease" source. Ho-boy. Check your electrics, utilize a G.F.I. and be careful/respectful re electricity; it can hurt you.
Bibliography Further Reading:
Hynes, Mick. 1993. Wire connections: the weakest link. Landscape & Irrigation Magazine 5/93.
Aurand, C. Douglas. 1986. Fountains and Pools-Construction Guidelines and Specifications, chap. 4 electrical system. PDA Publishers Corporation, Mesa, Arizona.