I also don't know what you mean by an "Ineffective plug-in protector" I have two plugs in my entire room and need 6 minimum besides this new one has a £30k connected devices warranty so if this goes wrong, Belken are paying out.
Power off by a switch means that computer is still connected to surges. Electricity that powers a computer is incoming on one wire (ie blue) and outgoing on another (ie brown). Surges are different. A surge is incoming on any or all three wires (brown, blue, and green). Open a switch (disconnect a brown wire). Surges are still incoming on other wires. Furthermore, protector parts simply connect an incoming brown wire surge to all other wires (green and blue). IOW protector parts can give a surge more potentially destructive paths into a computer. Can even bypass superior protection inside that computer. Where is the protection?
Best powerboard has no protector parts and has an always required fuse or circuit breaker. That means no parts that, in rare cases, create fires.
Does a millimeters gap in a switch stop what three kilometers of sky could not? Of course not. An open switch does almost nothing for protection. More robust protection is already inside a computer's PSU.
Anyone can make big quid warranty claims. Read its fine print. Protectors with large and hyped warranties are also full of fine print exemptions. Many learn this the hard way. Exemptions can vary even with different products from a same company. For example, some APC warranties stated that a protector in the building from any other manufacturer voided an APC warranty. Lessons from free markets demonstrate that products with largest warranties are often least reliable products. The technique is simple and well proven. Put numerous exemptions in the fine print.
If warranties prove product quality, then General Motors products are vastly superior to Honda and Toyota. Really?
Newsman demonstrated this in "SONY TiVo SVR-2000".
Eventually it boiled down to a line in the warranty that said "Belkin at it's sole discretion can reject any claim for any reason".
Protection (even 100 years ago) was about where hundreds of thousands of joules dissipate. How many joules do your protectors claim to absorb? Hundreds? Any solution that does not define energy dissipation is not doing protection. Protection means a surge current is not anywhere inside a house. Then a surge is not hunting for earth ground destructively via appliances.
BT suffers about 100 surges with each storm to their multi-million quid switching computers. And no damage. You do same. Earth that current before it can enter. That means a properly earthed 'whole house' protector. What actually does protection - a low impedance (ie less than 3 meter) connection to earthing electrodes. A current that connects short to earth then need not be inside hunting for earth destructively via your computer - or furnace, clocks, dishwasher, smoke detectors, etc.
That is how protection was done for over 100 years. That is why your town has phone service for four days after every thunderstorm. That is the only solution found in every facility that cannot have damage. That is also a least expensive protection per appliance. Proven solutions come from other companies of integrity including Keison, ABB, AEL Group, and Siemens.
Effective protectors claim protection from destructive surges. A powerboard protector claims to absorb how many joules? That is a near zero (typically not destructive) surge made irrelevant by protection already inside appliances. Lightning and other destructive surges can be hundreds of thousands of joules. Properly earthed 'whole house' protector dissipate direct lightning strikes in earth. And remain undamaged. Lightning may be 20,000 amps. So a minimal 'whole house' protector is 50,000 amps. Numbers define differences between effective and near zero protectors.
Protector light does not report on all types of failures. Your surge protector light only reports one type of failure - because that protector was grossly undersized. That light cannot report a protector as good. It can only report one type of failure - when a potentially destructive surge (ie too tiny to overwhelm protection inside a computer) destroyed a near zero joule protector.
Protection is always defined by numbers and a simple question. Where are hundreds of thousands of joules absorbed? A protector is only as effective as its earth ground which only exists with 'whole house' protectors. Only 'whole house' protectors have that dedicated and essential low impedance (ie wire with no sharp bends) connection to earth. An effective protector must always remain functional after every surge - including direct lightning strikes. Near zero (ineffective) protectors are identified by an extinguished "protector good" light. Apparently that is what you saw - and the resulting damage. Because a surge was not earthed BEFORE entering the building. Even power board protectors need protection only provided by the 'whole house' solution.
