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Two years ago I replaced my 20 year old central hvac unit (21/2 ton cooling, gas heat,) with a new 31/2 ton unit. The hvac contractor told me the old #10 romex,30amp double pole breaker and 30amp slo-blo fused service disconnect were adequate for the new unit so they were all left in place. Now I am blowing fuses at the disconnect. Two in one day this week. My compressor is rated for 40 amp max breakers. What can be causing the fuses to blow? Is #10 wire adequate or should I pull new #8 or #6? Can I use an un-fused disconnect and rely on breakers alone for protection? I can pull wire, make connections and mount the new disconnect myself but need to know if this is the right course. Thanks in advance for any help. steve
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Two years ago I replaced my 20 year old central hvac unit (21/2 ton cooling, gas heat,) with a new 31/2 ton unit. The hvac contractor told me the old #10 romex,30amp double pole breaker and 30amp slo-blo fused service disconnect were adequate for the new unit so they were all left in place. Now I am blowing fuses at the disconnect. Two in one day this week. My compressor is rated for 40 amp max breakers. What can be causing the fuses to blow? Is #10 wire adequate or should I pull new #8 or #6? Can I use an un-fused disconnect and rely on breakers alone for protection? I can pull wire, make connections and mount the new disconnect myself but need to know if this is the right course. Thanks in advance for any help. steve