2 systems 2 large amps one dedicated line

I have a 2 channel system and a surrond system, both use differant Mark levinson amps. Can the amps share the same dedicated 20 amp line. Since one is in stand by while the other is in use? the amps are Ml335 for the 2 channel and Ml332 for the surrond system. Amps are never on full power at the same time. Or the the amp not in use should it be fully powered off?
thanks Pete