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Old 12-17-2019, 01:11 AM   #27
westom westom is offline
Active Member
Jun 2009

Originally Posted by THE_FORCE View Post
Unfortunately, whole-home surge protectors donít protect against brownouts, which is what I am fairly sure now was the cause of the main fuses blowing in both the subs.
Brownouts never cause a fuse to blow. Fuses do not trip due to low voltage. Fuses trip due to excessive currents for a long time.

Low voltage does not damage any electronics. It is only a threat to motorized appliances. So long ago - long before any of us existed - an AC utility routinely provided sufficient voltage or cut off power. Because motorized appliances needed protection even long before WWII.

Voltage can vary so much that incandescent bulbs dim to 50% intensity or double intensity. Even a voltage that low or high is good (safe) for all electronics. As defined by international design standards that existed long before the IBM PC existed.

However, did you have a brownout? Or does another anomaly exist due to missing or defective hardware? Do lights change intensity when a major appliance powers off or on? In most cases, that poor workmanship causes no damage. In rare cases, intensity changes are reporting a major human safety threat. That defect (actually multiple defects are necessary) might explain that damage.

Addressing other myths. That reset button in a receptacle does nothing of the kind. An overload has no relationship to the many other possible anomalies including a ground fault. There is no magic device that protects from all anomalies - except where wild speculation, emotions, or hearsay invent knowledge.

Many electricians do not understand this. A 'whole house' protector can be just as ineffective as plug-in ones IF not connected low impedance (ie no sharp wire bends or splices) to single point earth ground. That protector never protects anything. It is effective only because it connects low impedance (ie less than 3 meters) to what does protection - those electrodes.

New fuse box says nothing about protecting appliances. Electricians are taught code. Code only discusses issues that might threaten human life. Issues that protect appliances are not defined in code. Code does not even discuss or define low impedance. Impedance is a different parameter that defines appliance protection. And not from brownouts or blackouts. That is but a completely different and unrelated anomaly.
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