In a star-delta starter, how can I incorporate a thermal overload relay as per Type 1 or Type 2 coordination?

Only tests carried out by accredited laboratories allow the announcement that a combination of equipment can protect the installation according to type 1, type 2 or total coordination.

These combinations are very clearly specified in tables by the manufacturer (Schneider) and do not allow any exceptions. See the link to these tables at the end of the folder.

When using a star/delta starter, the required level of coordination for the installation determines:

The ratings and part numbers of the 3 contactors
The ratings and part numbers of the circuit-breakers or isolators
The rating, part number and position of the thermal overload relay in the sequence


Type 1 coordination
The thermal overload relay is placed in the delta circuit and must be set to 0.58 x motor In.
The relay is less expensive as it has a low rating.


Type 2 coordination
The thermal overload relay is placed under the line contactor and must be set to motor In. It is not possible to obtain type 2 coordination by placing the thermal relay in the delta circuit.
The product is protected irrespective of the operating phase.


Information on coordination: Coordination 1 and 2

For extra info see attached selection guide taken from section A6 of our Motor Control and Protection catalogue

Released for:Schneider Electric UK