Nandi Powertronics Pvt. Ltd. Manufactures Fail-Safe Designed Circuit. Nandi Powertronics Pvt. Ltd. Has been achieved an ISO 9001:2000 certification. Fail-Safe Designed Circuit is available in wire-disconnection, component failure, and improper contact, inters lock failure, and then tries to configure things so that such failure will cause the circuit to act in the safest way.