Typical maintenance needed

[John Nystedt]

What is the typical maintenance (activity & frequency) required for a quality low voltage garden lighting system (other than lamp replacement)? Moonlighting, path lighting, downlighting, and recessed uplights are expected in the garden.

[sitelights]

Service/maintenance is required when a luminaire does not light-up when energized; when an individual luminaire does not light-up the cause is invariably one or more of four possible failures. Obviously, if nothing lights-up there is a power problem on the primary (120v) side or the secondary (12v) side of the transformer; this post does not address power problems.

Failure to light-up problems in order of frequency are: lamps, sockets, breaks in feed wire or main cable and connectors. Lamps and sockets are by far the most failure-prone items but lamp or socket failures are about equal and constitute roughly 95% of total maintenance. The lamp/socket failure ratio is about 50/50; about half of all "dark" luminaires in an operating system are caused by loose sockets or corroded pins (search "lamps and sockets"). This conclusion is based on 20 years in the field and careful record keeping.

Cable or lead wire breaks can be identified and repaired by pulling up the lead wire and running your fingers along the wire. It is easier to find a break by feel rather than by sight.

Connector problems are the next item on the trouble-shooting list (search "cable and connectors"). I prefer pierce point connectors for reasons cited in the posts on this topic.

Luminaire types and their susceptibility to failure or difficulty of maintenance is a function of installation, location and impact damage problems. I'm not a fan of "moonlighting" for aesthetic as well as service reasons (search "treelighting"). If a luminaire not designed specificly for downlight application is used the source of failure is normally water damage; the fixture body will fill with rainwater unless purpose built.

Pathlights are an overused design cliche and should only be used when absolutely necessary. Stemmed luminaires are particularly prone to impact damage: dogs, children, mowing, snow plowing or just plain tripping over them. Placement should acknowledge not only the appropriateness but also the probablity of being in the way of something or other.

Well lights or in-ground luminaires should be installed according to the manufacturer's instruction sheet; adequate drainage is crucial. If 50w lamps are necessary, spec a 75w rated luminaire; a 50w rated unit lamped at 50w is subject to meltdown if covered with mulch or leaves. Well lights without a covering lens can fill with mulch or shed leaves or needles; this is a definite fire hazard with high watt lamps since combustion temperatures are generated under conditions where the lamp surface is in contact with low flash point materials.

Regular maintenance is an inescapable aspect of low voltage outdoor lighting. At minimum a system should be checked twice a year. Note that every time a luminaire goes dark the voltage to the other lamps increases; if a system is not at 100% there is an inevitable and rising overvoltage that will shorten the life of the remaining operating lamps.

Clearly what is being provided to the client is lighting; they are not buying hardware or sweat: they are purchasing lighting effects. This is a service business and service is what keeps a system operating and a client happy. There are a number of posts relating to service issues at the topics referred to above. Contrary to some advertising claims, there is no such thing as a "maintenance free" low voltage lighting system.