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Lighting - HELP?
1 - Where Should / Can Lighting Be Located? 2 - New Construction or Remodel housing? 3 - Insulated, Double Wall, and Air Tight housings 4 - Bulbs - Types of Bulbs and Their Usage 5 - Housing Diameters and Bulb Usage 7 - Low Voltage (12V) or Line Voltage (120V) MR16 Bulbs? 8 - Lighting Controls - Setting the mood of your lighting system 9 - Choosing the Proper Housing and Trim 10 - Sloped Ceiling Housing and Trim Information
11 - Retrofit / Conversion Kits & Tools
12 - Fluorescent Bulbs AKA Lamps
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7 - Low Voltage (12V) or Line Voltage (120V) MR16 Bulbs?
Halogen MR16 bulbs come in 120V AC and 12V AC/DC. The 12V MR16 can also be used in DC applications, 120V MR16 can not. Both are 2" in diameter. Quartz-halogen lamps produce substantial amounts of ultraviolet light that needs to be filtered and the quartz capsule of the lamp can sometimes rupture or explode upon failure of the lamp. For these two reasons, some MR16 lamps include a cover glass that serves as an integrated ultraviolet filter and explosion shield. MR16 lamps lacking this cover require the use of a fixture that incorporates an external piece of glass specifically designed to provide this protection. The advantage of using Line Voltage (120V) MR16 bulbs is that the housings are less expensive because there is no need for a transformer. Also, dimmers and other control equipment are less expensive. Standard incandescent dimmers can be used with these bulbs. The draw back is that Line Voltage (120V) bulbs are not widely available. However, recently I have seen the 102V 50W GU10 variety at my local Home Depot. 120V 50W GU10 bulbs are also available via this web site. 120V MR16 bulbs use an aluminized reflector and therefore produce about the same amount of heat as a 50W PAR reflector bulb. There are those who claim that Line Voltage MR16 bulbs are not as bright and do not last as long as Low Voltage 12V MR16 bulbs. This has not been my experience. In fact, at one time my home had 12V MR16 lighting which I converted to 120V MR16 lighting. I am perfectly satisfied with the 120V MR16 lighting and recommend it as cost savings alternative to low voltage systems. 12V GU5.3/GX5.3 MR16 bulbs require there be a transformer in the circuit. Housings designed for use with 12V low voltage bulbs have the transformer built in. Transformers come in 2 varieties - Magnetic and Electronic. Magnetic transformers and some electronic transformers buzz or hum. Electronic transformers are the more costly of the two. Dimmers and other control equipment must be especially designed for use with Low Voltage transformers and are more expensive than incandescent dimmers and controls. Some electronic transformers, not all, can be used with incandescent dimmers. Low Voltage 12V GU5.3/GX5.3 MR16 bulbs are abundantly available in wattages from 20W to 75W and in multiple beam angles. 12V MR16 bulbs generally use a dichroic glass reflector which can direct as much as 80% of the heat generated by the bulb out of the back of the bulb. For this reason 12V MR16 bulbs generate more heat than the 120V variety and special housing precautions must be taken to adequately dissipate this heat. Both the 12V MR16 and the 120V MR16 bulbs have the same dimensions
in diameter and
basically look very much alike - but there are differences. What
is different about them is that the connector pin spacing (the
two little pins on the back of the bulb) and pin diameters are all slightly different.
A 12V 50/75W GU5.3 MR16 bulb will use a GU5.3 or GX5.3 pin spacing where
a 45/50W 120V GU8 MR16 bulb will use a GU8 pin spacing with a larger diameter pin
and a 50W Gu10 120V MR16 bulb will use a GU10 pin spacing which has two pins with a knob
on each end. The 120V 45/50W GU8 MR16 bulb is identical to
any 12V GU5.3 MR16 bulb in diameter (2") and in length (1 3/4") but the 120V 50W GU10 MR16 bulb, although the same diameter
(2"), is about 1/4" longer (2"). It is also important to
remember that a 120V 50W GU10 MR16 bulb must connect to a G10 base.
Likewise, a 120V 45/50W GU8 MR16 bulb must connect to a G8 base and a 12V 50/75W
GU5.3 or GX5.3 MR16 bulb must connect to a G5.3 base. These bases are not
interchangeable. The base and bulb pin spacing and pin geometry must
match.
Having different pin spacing and different pin geometry for different types of bulbs is intended to keep a 12V bulb from being used in a 120V application and visa versa. There are various connectors (pigtails with base) made to accommodate each type of bulb. These pigtails can be purchased separately and wire directly into the housing so you can use the bulb you desire. Just be careful to not attempt to use a 12V bulb in a 120V housing (no transformer) or a 120V bulb in a 12V housing (housing has a transformer). Usually these bulbs have 12V or 120V marked on the outer shell of the bulb. Also, these bulbs burn very hot and any oil from your skin that gets on the bulb (the little round thing in the center of the outer shell) will shorten the life of the bulb. The outer shell is a reflector and not part of the bulb itself. Therefore, the outer part of the shell can be touched during installation without causing problems. Due to the extra length of the 120V 50W GU10 MR16 bulb, the NL-470
series trim
(used with 4" housings) or NL-680 series trim (used with 6" housings)
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can not
be used with the 120V 50W GU10 MR16 bulb. This trim can only be used with the
120V 45/50W GU8 MR16 bulb or any 12V GU5.3 MR16 bulb.
We no longer carry the 120V GU8 MR16 bulb or base. Because of the
popularity of this trim and the desire of many to use it in a 120V
application, we have found
another source for the GU8 bulb and base. The 50W GU8
bulb and base can be purchased from the links below. You will not be purchasing the bulb or
base from us.