Are primary SPDs alone sufficient for equipment protection?
There is no one correct answer to this question. For a small facility, a single SPD installed at the service entrance panel can be sufficient, while for a bigger facility it is usually necessary to adopt a distributed protection philosophy where primary protection is installed at the service entrance panel, and secondary protection at branch panels.
There is no single answer to this question. From a small facility to a large facility, it is usually necessary to adopt a distributed protection philosophy where primary protection is installed at the service entrance panel, and secondary protection at branch panels. Each faculty requires individual analysis to determine the right protection to meet the needs of the equipment being used.
