How can I choose the electrical protection of a PLC?

The circuit-breaker must protect the PLC against high inrush currents on power-up and overloads during nominal operation.

• Magnetic protection (inrush current on starting) is provided by a iC60 Curve D circuit-breaker (see below for the choice of rating).
• Thermal protection must be provided by a thermal overload relay rated at the transformer secondary In.

Selection of circuit-breaker:
In the power supply module characteristics, it is the It current on activation that interests us (for each type of power supply).

Example:
BMXCPS2000 (see product data sheet)
It = 0.06 A at 240 VAC [Inom = 0.31 A]
The important operating point is located 10 ms into the circuit-breaker trip curve.
At 10 ms, we have an Iinrush = It/10 ms = 0.06/0.01 --> 6.0 A per power supply.

For further information about the protection that Schneider Electric can offer , please access to the next link:
https://www.se.com/ww/en/product-category/1600-electrical-protection-and-control/
https://www.se.com/ww/en/product-category/1500-contactors-and-protection-relays/

Released for:Schneider Electric Ireland