The Electrical Contractor Network

ECN Electrical Forum
Discussion Forums for Electricians, Inspectors and Related Professionals

Books, Tools and Test Equipment for Electrical and Construction Trades

Register Now!

Register Now!

We want your input!

Featured:
   

2017 NEC and Related
2017 NEC
Now Available!

   
Recent Posts
Sprinklered equipment 26-008
by bigpapa
12/02/16 04:24 PM
On Delay Relay with Auto Reset
by Potseal
12/01/16 09:59 AM
Wow, that was close!
by jraef
11/28/16 07:06 PM
Earthquake in New Zeeland
by RODALCO
11/27/16 11:25 PM
Calling all Non-US members!! (Non-US only)
by Tjia1981
11/27/16 06:33 AM
New in the Gallery:
12.5A through 0.75mm˛ flex (just out of curiosity)
Shout Box

Top Posters (30 Days)
gfretwell 13
HotLine1 9
Texas_Ranger 8
sparkyinak 7
Trumpy 6
Who's Online
0 registered (), 240 Guests and 3 Spiders online.
Key: Admin, Global Mod, Mod
Topic Options
Rate This Topic
#6906 - 01/14/02 10:32 AM High-Resistance Short?
Scott Offline
Junior Member

Registered: 01/14/02
Posts: 1
Hope I'm in the right forum here. I'm just Joe Homeowner looking for the answer to a puzzle. I recently replaced my two porch light fixtures using the existing wiring. Now the bulbs blow after only four or five days, and they are lit only from dusk to about 11 p.m. I read somewhere (of course I can't remember the source) that a high-resistance short can be caused from cracked insulation (very likely in this case)and that such a leak would not be enough of a short to trip the breaker but "at the very least you'll burn out your bulbs faster." Am I remembering this correctly? It doesn't make sense to me because wouldn't a short be a decrease in current to the bulb, not an increase? If I'm way off on this high-resistance short theory, any ideas on why I'm suddenly burning bulbs so fast? Thanks for any help.

Top
Work Gear for Electricians and the Trades

Work Gear for Electricians and the Trades
Work Gear for Electricians and the Trades
Arc Flash Clothing, Gloves, KneePads, Tool Belts, Pouches, Tool Carriers, etc. etc....

#6907 - 01/14/02 10:46 AM Re: High-Resistance Short?
resqcapt19 Offline
Member

Registered: 11/10/00
Posts: 2209
Loc: IL
One of the most common causes of early lamp failure is poor contact between the lamp base and the socket. This can produce enough heat to melt the solder at the base of the lamp and allow air to enter the lamb. Once air is in the lamp it will fail almost instantly. This problem can be caused by not screwing the lamp in tightly or poor quality sockets. What do the burnt out lamps look like? Most of the time if air has entered the lamp you will see some yellow stuff inside the glass.
Don(resqcapt19)
_________________________
Don(resqcapt19)

Top
#6908 - 01/14/02 12:07 PM Re: High-Resistance Short?
WARREN1 Offline
Member

Registered: 05/09/01
Posts: 184
Loc: Greenville, SC, USA
Interesting
Just yesterday, I noticed my bedroom walk-in closet light fixture was not operating properly. Turn it on, sometimes it works and sometimes doesn't. This is keyless type and has been in the house probably more than 30 years. Well, upon a little investigation, I finally see the little tip down in the bottom has a hole burned in it. So, when I moved the light bulb around, it made contact, but would not maintain contact. The house has an attic fan, and was used many years before we bought the house. We used it a few years, then added central AC. But the vibration of the attic fan would cause the incandescent bulbs to go out very quickly. After central AC was installed, the bulbs lasted much longer. My next step is to replace the fixture, with something a little better than a keyless.

Top
#6909 - 01/14/02 12:11 PM Re: High-Resistance Short?
Bill Addiss Offline
Member

Registered: 10/07/00
Posts: 4196
Loc: NY, USA
Scott,

If, as you say it is likely that there is cracked insulation somewhere "(very likely in this case)" I believe that you sould direct your attention to that first by having it looked at by a professional.

Perhaps they could also give you some ideas about the bulb situation while they are there.

Bill

Top



ECN Electrical Forums - sponsored by Electrical Contractor Network - Electrical and Code Related Discussion for Electrical Contractors, Electricians, Inspectors, Instructors, Engineers and other related Professionals