"This is a fairly well made but poorly designed product for 10sq.mm cable (it is actually made for a 3-phase supply). The earth and neutral terminals are too puny to take this size of cable and a rdige prevents using crimped ends (of the size for 10sq.mm) and I had to use a Dremmel to remove them. Very annoyingly, 25mm grommets are not supplied (the knock-outs are 25mm not 20mm) and Screwfix don't stock them (neither did elec factors in Pormadog, Barmouth and Bangor!). The earth and neutral terminal screws are too short to allow putting two 10sq.mm earth wires together (e.g. extra earth wire to SWA cable)."