i have a new garage with a 60 amp breaker running from the house to the garage. a new service panel with 240 volts line 1 red line 2 black . 240 vac across terminals. 120 vac from red to ground. 120 volts from black to ground. i am trying to install 6 light fixtures in ceiling. but i cant even get 2 of then to light up completely. when i turn on the lights my amp reading is only 4 amps on a 15 amp circuit . which is good. but my voltage drops down to 47 vac on that breaker to ground. and goes to 193 vac . on line 1 red to ground. so now i just discovered this weird voltage problem. my garage door has been working ok. but that breaking is dropping from 120 vac to 75 vac. how can i fix this problem ?
There's either a problem with the grounded (neutral) feeding the panel, or the one feeding the house. If you're only seeing the problem in the garage panel, and not the house. Then the problem is likely with the grounded (neutral) feeding the garage panel. Make sure the connections are tight, undamaged, and are not corroded. Also verify that the wire is not damaged, and is properly sized.
Depending on your level of experience, it might be time to contact a local licensed Electrician.