Homebrew PCBs

On 6/28/2016 5:20 PM, alan00463@... [Homebrew_PCBs] wrote:
>
> I'm making my first PCB for a thermostat for
> an electric heater.   I need to connect the
> electronics to several outside components:
>
>   - a thermistor that goes in the oven
>   - an thermal fuse to shut off power if it gets too hot
>   - battery power & ground
>   - 3-conductor connector to an external solid-state relay
>
> I plan to use pin headers and matching sockets for each of
> these four connections.    For each of these four connections,
> what criteria should I use to determine whether to put the
> pin header on the PCB and the matching socket on the connect-
> ing cable, or vice versa ?
>
> The thermostat itself and the SSR will fit into a plastic box that
> also contains the battery.    So my question pertains to orient-
> ing the headers/sockets inside the plastic box.   None of
> the connections will ever be disconnected without first removing
> four retaining screws from the lid of the plastic box.
>
> 
Hello, Alan--

Standard procedure is to put sockets on any group of wires that carry 
hazardous voltages
and thus could deliver a shock to an unwary person if the connector's 
pins were exposed.

Also, when unplugged, exposed pins carrying voltage will inevitably 
short-circuit themselves on any
nearby metal (that's one of Murphy's Laws)<g>.

Also, if you're using identical connectors, if possible you should 
provide a means of keying
or otherwise identifying which plug mates with which socket. If the 
connectors you're
using don't have provisions for keying, label the plugs and sockets.

HTH, and 73--

Brad  AA1IP