Exterior light (coachlights) problem (Dim lights)

Old 11-24-14, 07:25 PM
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Exterior light (coachlights) problem (Dim lights)

Ok, this is an old house with a ton of circuits and lots of unknowns (sadly). I found that the garage had a 30A circuit feeding it (2 overhead lights, 2 outlets and garage door). 2 years ago I installed 2 exterior coachlights by simply tapping on the existing circuit. Lights work fine, no issues other than a strange dimness. I have 6 more of these same coachlights installed on the exterior of the house all with about the same amount of brightness (using 100W bulbs). The two lights on the garage look more like 40W bulbs even though they have 100W bulbs install. I have lived with it since I installed them.

Today I noticed the exterior garage lights were on (turned on early, then forgot them). I noticed that the bulb on one light was quite dirty, so I thought I would pull it and clean it. When I pulled it, the other light went out (I put it back in place and the other light came on), which tells me that I wired these in series, but I think I am missing something very fundamental here. I can not see how having the bulb in place would complete the circuit to feed the other light. What am I missing? Also, could this be the root of my brightness issue?
Old 11-24-14, 07:54 PM
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If you wired them in series, yes that would absolutely explain your lighting levels.
Your filament is essentially a small resistor. So removing one bulb cuts the link to the other bulbs down the line.
Old 11-24-14, 08:55 PM
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This is much like old Christmas lights. I would consider rewiring all exterior lights. You did it once, you can do it again.
You also need to get rid of the 30A breaker, unless it's a double pole breaker feeding a sub panel in the garage.
Breaker size should be matched to smallest cable on circuit. #14 cable would be a 15A breaker, #12 cable would be a 20A breaker.

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