Dangerous shower with non-isolated supply?

[eem2am]

hello,

i am in Maryland, Ohio , and we are doing domestic showers which use stepper motors to control the water valves.

The energy to supply the stepper motors comes from the mains (85 - 265VAC) via an offline SMPS...................do you think that we will need to isolate the stepper motor supply rail?

...supposing we did NOT isolate the stepper motor supply rail...... (ie by not bothering to have adequate creepage and clearance in the SMPS transformer), then do you think that this would make it dangerous?, or more expensive to build the system?, since there is a potentially dangerous voltage in the motor windings, which is near to the water thats showering the shower user.

 

[flatulent]

If the mechanical connection between the motor and the valve is insulative, there should be no problem. You should consult the government regulations in your area. In some countries there cannot be even an electrical outlet in the same room as the bath/'shower so that no electrical devices can be used in the same room.

You may have to locate the device in the next room and run plastic pipes to the shower.

In addition, your device will probably have to be inspected and tested by a safety agency to get the CE mark or UL approval before it can be sold or used.

A further problem is getting liability insurance for your company. Even after passing all of the aprovals, you may not be able to find an insurance company that will issue you a policy at all or for an affordable price.

 

[eem2am]

thankyou

"If the mechanical connection between the motor and the valve is insulative, there should be no problem"

...........regrding your reference to such mechanical insulation.......

may i assume that you believe that the mechanical insulation would have to be heavier and more expensive , (and also be the subject of scrutiny by many regulatory bodies), than if i used an isoltaed SELV supply for the stepper motors?

i am just trying to assess which way would be cheaper.....isolating or not isolating the SMPS output ?

I dont want the hassle and expense of an isolated SMPS if i dont need it.