You should be looking for and energy management system, EMS. The coverage of these devices far exceeds simple "surge protection". The measure of the surge protection capability of a device is calibrated in joules. The higher the joule rating the higher the capability of the device to protect against an electrical surge. The EMS devices provide substantially more protection than a simple surge protection device. An argument for hard wired is the capability of a remote display, ie. the ability to monitor the device from within the rig. The hard wired device is much safer as regards the possibility that the portable device may be stolen however, that issue doesn't seem to be as big a problem in reality as it is in the fear of theft. It is likely that a review here regarding the selection of an EMS device is very likely to indicate a strong preference for the Progressive Industries products. Furthermore is also appears that PI has a far better track record as regards customer service and device support. The EMS devices are relatively expensive however, replacing a "bunch" of electronics on-board is clearly far more costly than the EMS device. A device that is simply a volt metre will tell you when the disaster occurred, assuming you are looking at the "thing" when the spike hit. A voltmetre simply measures current, it gives you absolutely NO protection from the damage that an electrical surge may cause. The moral of the story is again, you get what you pay for. Thinking a $10 voltmetre can appropriately and adequately replace a much more expensive EMS device is a fools folly.