Rated 5 out of 5Â by UKTroll Just use grease!
Not cheap, but excellent for bringing T&E tidily into knockouts. As they're designed to keep the water and dust out, they're very tight, but if you use a dab of silicone grease on the outside of the grommet and on the outside of the cable, both slide in really easily.
I keep a small tube of silicone grease in every toolbox for just this sort of thing, as it's non-reactive and helps all sorts of things slip in just fine!
Rated 3 out of 5Â by njg28 hard to fit
virtually imossible to fit onto 20mm knockout - no hot water available - as suggested by other reviews - so difficult without I didnt endd up using them
Rated 4 out of 5Â by Landrace Expensive, but does the job
Pricy for a glorified grommet but couldn't find similar very easily elsewhere.
Excellent for fitting normal T%E cable in a sheltered outdoor location. Otherwise would need round cable through a gland for max waterproofing.
NOTE: It is much much easier to fit if you drop it in some hot water first.
Rated 5 out of 5Â by davidqc Very handy
These simple grommets are a God send and no need for DumDum! Great for use in knockouts in say a garage/workshop (or other dusty areas) and outside (where cable enters bottom of the switch/outlet). I've got a 2.5mm and 2 x 1.5mm thro' these grommets (all three) without having to warm them up - just used a scewdriver to open the hole up a bit - and that was in temperatures of around 4deg C. But they are pricey for what they are though.