Switching Transformers

Sea Gull Lighting always recommends switching transformers used with the Ambiance® Lighting Systems on the line voltage (120V or primary) side of the connection for optimum performance and safety. The following illustration should help define the rationale.

For illustrative purposes, we will use a residential situation. Residential switches are rated for a maximum load of 15 amps or 1800 watts (15 amps X 120 volts=1800 watts). If we have a hypothetical Ambiance® Lighting System installation totaling 300 watts, watch what happens.

Assuming the standard formula of Amps=Watts/Volts, at 300 watts a 12 volt system would produce 25 amps.

300 watts / 12 volts = 25 amps
Too much!!

This is obviously too great for a 15 amp switch. However, the same 300 watts on the 120 volt side produces a mere 2.5 amps which is, obviously, perfectly acceptable.

300 watts / 120 volts = 2.5 amps
Just right!!

So, therefore, we always recommend switching on the primary (120 volt) side and not the low voltage (secondary) side.

For applications which require switching to be done on the low voltage (secondary) side of the connection (an extremely rare situation), there are important factors which need to be considered. When switching the secondary side of the connection, it is very important that the switch used is rated for the amperage created and that the wattage load (when switched) never drops below 50% of the transformer's rated capacity. But don't'try it!!!

For the sake of your safety and the simplicity of the installation, Sea Gull Lighting does not recommend that you switch on the secondary side.

To calculate amperage, use the following formula:

Amperage = Wattage / Voltage