After a lightning strike to a tree ~60' from our residence - that blew out windows, fried electronics throughout the house, dislodged tiles, cracked ceiling, etc. - we've had a series of ongoing electrical problems, including a melting (shorted) outlet, electrical equipment failure, flickering lights, etc. Now an electrical engineer is proposing a Megger test, and suggests using 250 VDC. We've seen that Megger testing of households is often done at 500V, but he indicates that using the higher voltage might damage our system. Any thoughts on the advisability of higher or lower voltage Megger testing would be appreciated. Also, what else, beyond the Megger test, should be done in the way of inspection of our electrical system?