gary
Senior Member
- Location
- California
- Occupation
- Retired electrical contractor / general contractor
I finished wiring a large custom home in August, 2004.
Two weeks ago, the 48? 4-tube florescent fixture in the laundry room stopped working.
The owner replaced the original four Phillips 34 watt ?Econ-O-Watt? T-12 bulbs, but the fixture still would not work.
Assuming that the ballast was bad, the owner installed a replacement that he says was identical to the original. Now the fixture would light up, but the 20 amp AFCI breaker would often trip when the light was turned on.
Taking a closer look at the label on the ballast, he noticed that the new ballast specified it was for use with T-8 bulbs, so he installed a set of 32 watt T-8 bulbs. Again, the fixture would light up but often tripped the AFCI.
At this point, he called me for help and wanted to know if I thought the breaker could be bad. I told him I thought it unlikely that the breaker would just happen to go bad at the same time he was working on this fixture. I offered to take a look but he wanted to try to fix it himself, so I told him to make sure the wiring matched the diagram on the ballast, that the connections were all tight, that the bulbs were properly seated, and that wires were securely attached to the lamp sockets.
Unable to find anything wrong with the installation, he now assumed that the new ballast was defective or had been damaged by the T-12 bulbs. After installing another new ballast with T-8 bulbs, he found that the AFCI still tripped!
Another electrician who lives near the owner suggested there might be something wrong with the light switch, so he replaced one of the 3-way light switches. The AFCI still tripped.
Yesterday he called & said he?d bought a new AFCI but wasn?t sure how to install it and could really use some help. It took me half an hour to get there through the holiday traffic. I was surprised to find that the fixture was ?on? when I arrived. He explained that sometimes the fixture would light without tripping the breaker and could then be left on for hours without any problem. This was a windowless room between the house and garage so they?d been leaving it on a lot! I found that switching the light on would trip the breaker about 50% of the time. I could find nothing wrong with the fixture wiring. Rather than opening the blister pack on his new breaker, I tried temporarily moving the circuit to one of the other AFCI?s already in the panel. It also tripped when the light was turned on! At this point I thought there must be a fundamental compatibility problem between the breaker & the ballast. As a last resort, I suggested we go ahead and try the brand new breaker hoping that during the past two years Siemens had somehow improved the product. Lo and behold, the new breaker resolved the problem!
The original ballast had been discarded, so I was unable to verify that the replacement was in fact identical to the original. I didn?t think T-12 bulbs would work at all with an electronic ballast. Is it possible that they ?worked? but drew excessive current causing the original ballast to fail after 2 years?
In hindsight, the owner was right in suspecting from the beginning that there was something wrong with the breaker. Are there known breaker / ballast compatibility issues that I should have been aware of? I searched this site for ?AFCI? didn?t find that there were too many reported problems with the breakers. I?m going to call Siemens next week & see if they have an explanation. At this point, talk of greatly expanding the role of AFCI?s in the next code cycle is making me a little nervous!
Two weeks ago, the 48? 4-tube florescent fixture in the laundry room stopped working.
The owner replaced the original four Phillips 34 watt ?Econ-O-Watt? T-12 bulbs, but the fixture still would not work.
Assuming that the ballast was bad, the owner installed a replacement that he says was identical to the original. Now the fixture would light up, but the 20 amp AFCI breaker would often trip when the light was turned on.
Taking a closer look at the label on the ballast, he noticed that the new ballast specified it was for use with T-8 bulbs, so he installed a set of 32 watt T-8 bulbs. Again, the fixture would light up but often tripped the AFCI.
At this point, he called me for help and wanted to know if I thought the breaker could be bad. I told him I thought it unlikely that the breaker would just happen to go bad at the same time he was working on this fixture. I offered to take a look but he wanted to try to fix it himself, so I told him to make sure the wiring matched the diagram on the ballast, that the connections were all tight, that the bulbs were properly seated, and that wires were securely attached to the lamp sockets.
Unable to find anything wrong with the installation, he now assumed that the new ballast was defective or had been damaged by the T-12 bulbs. After installing another new ballast with T-8 bulbs, he found that the AFCI still tripped!
Another electrician who lives near the owner suggested there might be something wrong with the light switch, so he replaced one of the 3-way light switches. The AFCI still tripped.
Yesterday he called & said he?d bought a new AFCI but wasn?t sure how to install it and could really use some help. It took me half an hour to get there through the holiday traffic. I was surprised to find that the fixture was ?on? when I arrived. He explained that sometimes the fixture would light without tripping the breaker and could then be left on for hours without any problem. This was a windowless room between the house and garage so they?d been leaving it on a lot! I found that switching the light on would trip the breaker about 50% of the time. I could find nothing wrong with the fixture wiring. Rather than opening the blister pack on his new breaker, I tried temporarily moving the circuit to one of the other AFCI?s already in the panel. It also tripped when the light was turned on! At this point I thought there must be a fundamental compatibility problem between the breaker & the ballast. As a last resort, I suggested we go ahead and try the brand new breaker hoping that during the past two years Siemens had somehow improved the product. Lo and behold, the new breaker resolved the problem!
The original ballast had been discarded, so I was unable to verify that the replacement was in fact identical to the original. I didn?t think T-12 bulbs would work at all with an electronic ballast. Is it possible that they ?worked? but drew excessive current causing the original ballast to fail after 2 years?
In hindsight, the owner was right in suspecting from the beginning that there was something wrong with the breaker. Are there known breaker / ballast compatibility issues that I should have been aware of? I searched this site for ?AFCI? didn?t find that there were too many reported problems with the breakers. I?m going to call Siemens next week & see if they have an explanation. At this point, talk of greatly expanding the role of AFCI?s in the next code cycle is making me a little nervous!