Hi all I'm a recently qualified domestic electrician, struggling to come to terms with the reality of testing for certification - it's a joy isn't it? The whole thing is a ball-ache, but I have a particular problem; insulation resistance testing on a pre-existing domestic installation. It would be a lot of work to locate and remove/disconnect every accessory on the lighting/power ring finals and finals - so I'm doing L&N to E tests. Problem is, even doing this I'm getting close to zero results at 250v. I've tried using the busbars and MCB outlets, and disconnecting the live conductors and earth from the CU - still getting nowhere. Please - any wisdom/ideas greatly appreciated. 2 hours work installing followed by 3 hours trying to do the bl**dy tests isn't funny, or economic. I'm prepared to be stupid/wrong/ignorant, and am always ready to learn.