replace service panel for air conditioner


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Old 06-09-02, 07:04 PM
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replace service panel for air conditioner

My air conditioner stopped working last week. Turns out it was a fuse in an outside service panel that runs the compressor. I am not that familiar with these types of service panels (compared to a regular service panel with breakers). The panel has a single black fuse holder for two buss fuses (TR50R ???) . You pull out the fuse holder to cut the power or replace the fuses. (By the way, this service panel is fed from two 50amp breakers in my main panel inside the house).

When the holder was removed, there was a tar like substance on the contacts mostly covering the inside of the holder. It smells somehing like a blown light ballast. Would something have metled in the old blown fuse? Should I be replacing the service panel with something more current? I also found several old bee's nests in there.

My air conditioner service guy said about $30 to replace it so I figure I can probably do it for at least half.

Any suggestions or comments?
 

Last edited by pjaffe; 06-10-02 at 07:32 AM.
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Old 06-10-02, 06:14 AM
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The A/C fused cutout at the condenser, that you describe is currently being installed every day. Yes, replace it with the same style fused cutout. It is possible that the bee's nests or loose conductors it the terminals caused high current flow and made the fuses blow.
 
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Old 06-10-02, 07:31 AM
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replace 50 with 60amp?

I shopped Home Depot this morning to learn the terminology and see what the products were. All I saw were 60 amp fused or non-fused panels. My panel uses 50 amp fuses and the breaker in the house is 50 amp. Wouldn't going to a 60 amp fused panel be the same as using a non-fused since the inside breaker would cut out at 50 amps?

Also, when it says 60 amp, it means that it would use two 60 amp fuses? Right?
 
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Old 06-10-02, 07:45 AM
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Most A/C units require fuse protection which is why they are at the unit. Most new main panels have circuit breakers, which is why there is a 50A breaker feeding the two 50 fuses at the unit.
You must use a 60A fused disconnect with fuses to match the ones in the old unit. 60A disconencts can be purchased with one two or three fuse positions, so be sure to buy the right one to replace the old one.
 
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Old 06-10-02, 10:38 AM
Wgoodrich
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HandyRon, you are saying opposite of what I have experienced. What I have seen is that most HVAC units list either HACR or fuses on the name plate instead of specifying fuses only. Is something happening that I am missing or have you checked the markings on the name plates of a/c units on an average in the recent years. Curious why we are thinking opposite in this trend concerning hermetic motors.

pjaffe, check you name plate and see if that name plate specifies only fuses or mentions HACR breakers. If that name plate states fuses only then HandyRon is right you will have to install fuses.

Problem that I see is that you have a breaker in the distribution main service rated panel located ahead of the fuses in the disconnect serving that a/c unit. If the a/c unit states fuses only then that breaker in the main service rated panel is not allowed to control that a/c branch circuit.

Check your a/c unit's name plate in the block on that a/c name plate that says "maximum overcurrent protection" or "MOP", and tell us if it says fuses only or mentions HACR breakers, then we can tell you if you can use a non fused a/c weatherproof diconnect or if you must install a fused disconnect.

Curious

Wg
 
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Old 06-10-02, 07:41 PM
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If you choose to replace your fused disconnect with a non-fused disconenct, there are more questions to ask first.
WG is correct that if the unit states fuses or circuit breaker protection, then you COULD rely on the circuit breaker to protect the wiring and the equipment.
I have found that most units do permit fuses or circuit breakers too.
Be sure the breaker is HACR type.
 
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Old 06-11-02, 05:27 PM
Wgoodrich
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HandyRon, I believe that most household breakers of the better brands are also HACR breakers. However they should confirm the breakers are HACR breakers because I have found a few of the more inexpensive and I am saying that diplomatically as more inexpensive breakers are not HACR. Although there are only a few brands of breakers that are not HACR they are still out there as not HACR approved. You made good advice on that HACR recommendation.

Wg
 
 

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