I bought an electrical device a few months ago. A few weeks ago, it failed, complete with the release of magic smoke. I contacted the company, and they've had me mail it to them and have been investigating the failure.
Today they contacted me asking to have an electrician come to my house and take some measurements; they said that they've talked to experts and they "...have indicated that a grounded neutral in a house with wiring like yours may create a scenario that could cause something like this."
My house was built in 1959, and while some circuits are grounded, the room where the device was plugged in has two-prong outlets, and the cable going to the receptacles is ungrounded. The device used a two-prong plug.
I'm inclined to let them do the measurements, but before I do, I'd like to know:
What is a 'grounded neutral'? My main breaker panel only has two breakers, one 30-amp for the A/C and one 100-amp breaker for the subpanel that powers the rest of the house; I'm pretty sure that Neutral and Ground don't touch inside the subpanel, but I haven't looked inside it for a couple of years.
Is there anything else I should know?