Section 183.440 - Secondary circuits of ignition systems(a) Each conductor in a secondary circuit of an ignition system must meet SAE Standard J557.(b) The connection of each ignition conductor to a spark plug, coil, or distributor must have a tight fitting cap, boot, or nipple.CGD 73-217, 42 FR 5944, Jan. 31, 1977, as amended by USCG-1999-5832, 64 FR 34716, June 29, 1999