Landscape Architect Articles

LCN February 2007 Landscape Lighting02-28-07 | News

The Use Of Water-Safe Versus Water-Proof Lighting

By Perry Romano, IESNA, LC

A large, eye-catching fountain in a motif associated with ancient China, is illuminated with 250-watt metal halide uplights. These bring out the form of the ?EUR??,,????'??beast,?EUR??,,????'?? casting a very white light with accurate color rendition and operating economy.

Is the following statement true or false? ?EUR??,,????'??Water-safe landscape lighting is not always water-proof, but water-proofing lighting is always water-safe.?EUR??,,????'??

(Answer at end of article)

Where they already are present, or can be introduced to a public or private property, water features are a key element in successful landscape design and installation. The always appealing ?EUR??,,????'??look?EUR??,,????'?? and sound of water introduces interest and serenity, and is often the primary focal point. Certified electricians, by title or function, do not install many waterfalls and fountains. Instead, most of these features are installed by irrigation systems or landscape contactors.

As a consequence, the focus of this article is ?EUR??,,????'??water-safe lighting?EUR??,,????'?? for landscape features like ponds and decorative fountains?EUR??,,????'??+not lighting for swimming pools and spas.

This fountain uses a single underwater floodlight, illuminated with an energy-saving 20-watt MR16 12-volt halogen lamp. It is the focal point for the backyard, while providing ample economical light to accentuate details.

Water-Safe Versus Water-Proof Fixtures

Most above-ground landscape lighting fixtures are considered water resistant in terms of enduring rain, melting ice or snow, and some degree of splashing. They are tested by the manufacturer and by an independent electrical-safety laboratory (such as UL or ETL) for wet-location use. This is not the correct criterion for the landscape contractor to use, however, for submersible fixtures. Fixtures used underwater are very different from those used in the rest of landscape lighting. Submersible fixtures must be entirely sealed to prevent any water or condensation from entering the lamp housing.

Many underwater fixtures cannot, in fact, be used out of water, since they may actually rely on surrounding water to dissipate lamp heat. Landscape contractors should seek lighting fixtures designed for use below water level (submersible) or above water but still in or immediately adjacent to. Underwater fixtures must be tested and labeled by a nationally accepted independent testing laboratory specifically for submersible use. Even stray voltage from 12-volt fixtures can kill a client?EUR??,,????'???s pond fish.

A water-resistant fixture is seen here among a rock garden and its plantings. It can be aimed to direct light to selected features. An energy-efficient 12-volt, MR-16 halogen lamp projects intense, white light at low watts.

Materials

Water-safe lighting fixtures must be able to hold up when continually exposed to the corrosive nature of air, water and soils. When installing lights in or around water gardens and fountains, be sure to choose housing materials of brass, stainless steel, or the new composite materials. These are the most durable, corrosion-resistant choices. Aluminum, often good for building- or wall-mounted applications, is not a good choice for in-water. Aluminum not only can deteriorate, but cast aluminum is actually porous, allowing water to leak.

While brass is the most popular choice in corrosion-resistant, water safe/water proof landscape lighting fixtures, stainless steel is often overlooked. It can sometimes be more ?EUR??,,????'??seamless?EUR??,,????'?? with its surroundings, whether used above ground or in a body of water. A 12-volt, 50 watt PAR 36 lamp is inexpensive to buy, replace and operate. It casts a broad beam of warm light that can be aimed in different directions.

Safety

Any landscape contractor needs to know enough about wiring to ensure that the installation, its components and connection points, are safe and will work. The National Fire Protection Association produces and updates a handbook and website about the National Electrical Code. This document serves as the basis for local and regional safety regulations. Check requirements of the NEC carefully, before purchasing or installing any submersible landscape lighting fixtures, with which you are not already familiar.

Low-voltage transformers approved for ponds must have an isolated secondary transformer, UL or ETL listed and labeled as such for pond lighting. 99% of transformers are not waterproof?EUR??,,????'??+weatherproof yes, waterproof no.

Transformers should be plugged into outdoor Ground-Fault Circuit-Interrupter (GFCI) receptacles. When adding an electrical outlet for a water garden or water-based landscape feature, keep this outlet a few feet off of the body of water. A ground-fault circuit interrupter shuts off a circuit instantly if it senses a hazardous short.

The GFCI receptacle looks like a regular receptacle except it has a reset button in the middle. In new construction, these are usually required in bathrooms, kitchens and outdoors. Often a GFCI is mounted as the first receptacle along a circuit, between the electrical panel and other receptacles on the same circuit, automatically protecting others on the same line.

A fountain at a corporate entrance uses underwater ordinary line-voltage 50-watt metal halide fixtures. They provide both ?EUR??,,????'??glitter?EUR??,,????'?? and highlights outside and inside waterspouts, consume relatively little electricity, cast a very white light and have long operating life.

Waterproof Covers

Waterproof covers should be added to all outdoor electrical outlets, to ensure that switches in the breaker panel do not shut off important water filtrating or oxygenating equipment if water penetration in the outlet causes a breaker to trip.

Extension cords should simply not be used when a water feature is added to the landscape because, when used over long periods of time, extension cords can cause fires and be subject to gnawing rodents and insects. If their use is necessary, cords and low-voltage wires should be run inside corrosion-resistant conduit so the chance of cuts in the wire and electrocution of land- or water-based species are minimized. Unplug everything (do not merely shut off the switch) to prevent shock and the serious injury when re-lamping, moving lights, fixing waterfalls, pond filtration systems or other features.

As an example of perfect lighting and visual balance, this backyard pond uses underwater, 12-volt, 35-watt halogen floodlights in combination with above ground, 12-volt, 10-watt halogen pathlights. Together, they not only create a focal point, but also give the scene dramatic depth perception at night.

Extra Wire

When laying pond or other water lights into place, leave two or three feet of wire at the fixture to facilitate lifting the light fixture clear of the water for lamp replacement or other service. A good time to review sockets and check for rust or corrosion in or around water features is each time a lamp needs to be changed.

Lighting Basics

The beauty of a lighted waterfall, pond or fountain can be breathtakingly ?EUR??,,????'??magical?EUR??,,????'?? at night. There is something special about seeing the elegant movement of colorful fish passing along underwater lights. Lighting water need not be complicated. One, two or three well-placed underwater floodlights in a smaller pond may be all that is needed to bring out the beauty of underwater plants, fish and decorative stones. A natural-appearing waterfall will be best illuminated using above-ground surface floodlights around the perimeter.

If you have surrounding foliage, you may want to add path lights around the back edges to bring out depth perception. Use path lights that hide the light source, to eliminate glare. People enjoy lighted ponds and fountains more at night than in daytime. Keep your landscape lighting in and around bodies of water simple and subdued. With water-safe lighting, more is not always better.

PS: The statement at the beginning of this article, as you now know, is definitely true!

Pathlights, using mere 10-watt 12 -volt incandescent lamps, can be used to light more than paths. This example shows fixtures with glass lamp holders in different colors, for a unique nighttime environment of plants, flowers and paths.