Dry contacts offer isolation, flexibility, and protection, making them a great choice for circuits that require safety and precision. Dry. Protective relays and devices have been developed over 100 years ago to provide “lastline”of defense for the electrical systems. The selection and applications of. It's not the RELAY that is wet or dry, it is the CONTACTS of the relay. A "dry" relay contact is not connected to the power source that operates the coil of the relay, so it can be a different voltage on the dry contact that what operates the relay coil. for example your relay has a 24VDC operating. What measures can be taken to protect the relay itself and handle electrical surges and spikes in an industrial environment? Typically, I place a flyback diode on the coil to prevent back EMF. In one circuit, we've used an NTC to prevent inrush current. Doing so may result in reducing Relay performance for insulation failure, contact welding, and contact faults, and might even result in burning or other damage to the Relay itself.