Arrived on site to install heat pack in rooftop heat pump. Discovered wire coming from breaker panel in garage is a 10 gauge wire which is too small to run this heat pack. Checked rooftop unit we installed a couple years ago and that unit also has the undersized 10 gauge wire. Customer will need to contact a licensed electrician to run 6 gauge 3 phase wire from panel in garage to all 3 roof top units. The 30 amp and 40 amp 3 phase breakers powering the newer roof top units will need to be up sized to 50 amp 3 phase breakers to match the breakers on the heat kits. The oldest roof top unit is only a 3 ton heat pump with a 10kw heat pack running on a 30 amp 3 phase breaker and may not need to be swapped out but wire should be up sized for that unit as well per electrical code. Chud will return and finish installing heat pack when the new wires are ran up to the roof top units.