I.S. Solenoid Valve

You should mentioned Watt (coil power useage).

Both the inrush current and Holding current are important.

INRUSH current is mandatory

Is there an inrush current in a DC solenoid ? Not unless there is an economy-resistor/double coil solenoid. Even then, the inrush is momentary, and must be integrated knowing the duty cycle...

1. How to ensure that cable can carry sufficient current supplied by barrier required for solenoid operation? Is there any calculation ?

The same way that you worked out that the voltage drop was acceptable.

A1a) Test it.

A1b) Compare it with installations elsewhere.

Bear in mind that it is not the solenoid valve that is intrinsically safe. It is the method of protection of the hazardous area that is instrinsically safe provided all the components including the solenoid valve are designed, selected and installed so as to form an intrinsically safe system.

• At 35m, another option would be to put the solenoid valve in a safe area and run an air line to the equipment in the hazardous area. That way, the barrier can be dispensed with.
• Another option, provided the solenoid valve was in either Zone 1 or Zone 2, would be to use a solenoid valve that was EEx d - "flameproof" - and dispense with the barrier.

Do not design, specify, install or maintain hazardous area electrical equipment without having undergone a suitable training programme.

In an intrinsically safe circuit the voltage drop is less important than the amount of energy stored in the cable. View the cable as a capacitor/inductor in series with your solenoid. The barrier limits the amount of energy passing into the hazardous area to a level so that if a fault were to occur, the resulting spark would not be sufficient to ignite the gas. Too much energy stored within the cable renders the barrier useless. Do not rely on any advice provided by this sort of forum. Make sure that you take expert advice. Your MTL rep will be trained to help you, and will have recommendations and tables available.

Hi

thanks all for your valuable advice.

thanks.

Go and get that training.

if the valve is truly rated for a hazardous environment, then the manufacturer is required to supply a "Control Drawing" which shows how the device is to be used. Refer to the manufacturers specifications first, then proceed with your other calculations.