PAT testing extension reels

Hi all,

I carry out Level 1 electrical inspections at my workplace using a Seaward 250+ tester. My 2 questions relate to extension reels. I usually have my Earth Continuity limit set at 0.1 Ohms and, for most extension reels, following calculation of the 'R' value of the cable, have overridden automatic fails (below 0.5 Ohms), in order to proceed to the Insulation Test. I am currently trying to test a 45 m reel, which I have fully unwound. The Earth Continuity is high, as expected, at 0.7 Ohms. As I cannot override the 0.5 Ohms maximum threshold of my tester, I cannot proceed to the Insulation Test. Is it acceptable to 'PASS' this appliance, as long as I note in the records that an Insulation Test was not possible to carry out? My second question is regarding safety cut-offs. The 45 m reel has a thermal cut-out, but am I correct in thinking this doesn't offer sufficient user protection, and that a plug-in RCD should be used whenever this extension reel is in use? I would really appreciate any advice regarding this, as I want to ensure I provide my colleagues with accurate information and appropriate protection. Many thanks in advance, Becky.