Blocks advanced for better connections
Tom Shelley reports on a number of enhancements that greatly improve a humble but essential part of all automation systems
A new range of terminal blocks includes no less than 12 patented innovations to reduce the risk of incorrect connections, reduce width and improve ease of use. Electrical connections remain the weakest link and most common cause of problems in electrical systems of all kinds, and are especially troublesome when they combine with the effects of human error. According to Ian Sweatman, product manager low voltage automation products for ABB, seven of the patents relating to the SNK range have been published, the most obvious of which is the fact that the blocks are asymmetric with two flat surfaces, to which labels can be attached and which can be seen both from the front and the side. Labels can either be stuck on, of made as pre-printed or hand written marker cards that are held on using two slots, with single exits on alternate sides, so the markers cannot slide out and get lost. They are also up to 3mm narrower than conventional blocks. Sections in the mouldings allow the narrowing without loss of rigidity. DIN rail foot clamps have one foot fixed, while the other moves, with a peg to prevent too much movement and possible breakage. Where used, jumper bars go in with a positive click and cables access through small funnels, which guide their ends into the screw apertures. An anti-release screw design prevents wires becoming loose. A single version meets all leading conformity standards, including: ATEX, UL, UL94 V0, Gost and CSA as well as being RoHS compliant. The series is available in sizes from 4mm2 to 95mm2 as feed through terminals, accepting cables down to 0.2mm. Double deck and disconnect versions are also available in 4mm2 and an optional 6mm2 if required. Completing the range are fuse terminals that accept 5 x 20mm and 5 x 25mm fuses.