Electrical apparatus with higher durability against surges

An electrical apparatus which is placed immovably in a facility, comprising:

• a plurality of input-terminals being selectively electrically connected to a power source, the plurality of input terminals being electrically mutually parallel to the power source;
• and
• a plurality of electric circuits each having at least one resistance element, the plurality of electric circuits being, one-on-one, electrically connected to the plurality of the input terminals, and being arranged positionally closely with each other on a board,
• wherein each of the electric circuits comprises
• a desired functional circuit being electrically connected in series to the resistance element,
• a protection circuit being electrically connected in series to the resistance element and connected in parallel with the functional circuit, the protection circuit being configured to electrically protect the functional circuit from an excessive voltage applied across the functional circuit, and
• a discharge member being electrically arranged in a path connecting the input terminal and the functional circuit and being arranged to form a discharge gap which faces a discharge member of an adjacently arranged electric circuit included in the plurality of electric circuits, the discharge gap urging an electrical discharge between the discharge members of the mutually adjacently arranged electric circuits connected respectively to corresponding input terminals included in the plurality of input terminals when a voltage applied to the electric circuit selectively electrically connected to the power source exceeds a predetermined voltage value, part of the corresponding input terminals being selectively electrically connected to the power source and a remainder of the corresponding input terminals being electrically disconnected from the power source.