If no agent has been so appointed, service may be made by giving a like copy to any person upon whom service could be made in an action at law against such public utility, or by sending the same by mail, postage prepaid, addressed to such public utility at any usual post office address of the same.
Source. 1915, 99:4. PL 238:30. RL 287:31. 1951, 203:11 par. 32, eff. Sept. 1, 1951.