Hi guys, Does anyone know of any good references or rules-of-thumb for creepage, clearance and track width when designing high-voltage/high-current kit? With the parts I've managed to find, at least two PCBs in the mini-oven will need to operate at mains potential -- the power supply and the power-switching for the heating elements. There will be about half a dozen tracks on the switch board running at mains potential, and two on the power supply board. What I need to know is: - How thick these tracks need to be to carry 1650W - Same again for about 15W (the PSU uses a 6VA transformer -- "double it and add a bit") - How much distance I need to have between live and either neutral or a switched HV track. I've had a play with a few creepage/clearance calculators, which suggest that I need a minimum 0.1in gap between L and N at ~300V. So if I was to use 100mil (0.1in) tracks, those tracks would have to be placed on a 200mil grid (assuming they were completely straight) in order to meet that spec. This is based on the output from but other calculators seem to come up with similar results. What I haven't managed to find yet are any guidelines on the required track width for carrying, say, 1650W at 240V (about 7A)... Can anyone suggest any rules of thumb for this? The PCB blanks I'm using are 1oz single-sided, FR4 laminate. If anyone wants to go looking up the datasheet, they're Farnell part number 320-4911, "FR4 composite, pre-sensitised PCB laminate, Eurocard size, single-sided". As this is a one-off, tinning the high current tracks, or soldering bits of wire to them to increase the thickness (and thus the track area and current handling capacity) is also an option, if it makes things significantly easier. I've seen this done in SMPSUs, if it works for them... *shrug* Thanks, -- Phil. piclist@philpem.me.uk http://www.philpem.me.uk/ -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist