We just replaced the HVAC system including the condenser with high efficiency Westinghouse unit. The condenser is a 4 ton model ES4BD 048KA. There are two #8 wires feeding the unit from the 200A service panel. The double breaker was replaced as well with a 50A unit and the voltage from the local utility is well within range. There is about an 80 foot run from the service panel to the disconnect at the condenser. When the condenser kicks in, the amperage spikes to ~120 amps on one leg and 90 on the other, and there is a short duration but pronounced buzz from the conduit running in the house. The old unit did the same thing as far as the buzz (not sure about the readings) but what has me concerned is the amperage imbalance and the annoying buzz. Not to mention, our electric bill for the last month (granted it was warm and the AC ran quite a bit) was 2X any bill we had ever seen... even with the 20 year old condenser we just replaced. A local electrician came to investigate yesterday and installed an additional capacitor on the compressor side of the dual cap that came with the unit. The amperage dropped to about 112 and the buzz is somewhat dampened. He claims, as do others, that it is the cable jumping in the conduit. So, the question is, does any of this make sense and what if anything outside of replacing all the conduit and wire can I do to remedy the noise, the imbalance, and the OUTRAGEOUS electric bill?

Thanks for your help.

If those are the old number 8 wires that were used with the old A/C outside unit I would be sounding (Meggering) those out to be sure they are OK. The voltage draw should not be so lop sided and I would also check to be sure nothing else is tapped off those wires feeding something else because those readings are way to high. The conduit buzz could be a short/high leg seeking ground. Look at the rate plate on the new unit. It will tell you what the draw should be and both legs should be even.

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