Generally in electrical system with multiple neutral-to-ground connections, (e.g. the main and Standby/Emergency power supplies) the neutrals of the two systems must be separated to assure proper ground fault current sensing. When the separated ground fault in two systems is mandatory, the incomplete sensing and nuisance tripping can be eliminated by 4 Pole transfer switch application, which will also classify the Standby/Emergency supply as a separately derived system. On the other hand some standards such as Canadian Electrical Code does not require, nor is it general practice to provide additional ground fault protection where the essential loads are energized from a separately derived power system, such as an engine-driven generator set. However according to some recommendation no ground fault protection is applied to any emergency system where the capacity of a generator is 500 kW or less. This is a trade-off in possible electrical equipment damage, in order to keep the essential circuits in operation, as decided by an operator. Therefore if individual ground fault protection is your concern you shall use 4 pole transfer switch for suitable neutral/ground separations.