Hi, if you are looking for surge protectors, Powerworx is the right one..it help to protect your sensitive electronics from damaging that occurs due to harmful spikes and surges.

 

Excellent information on surges and surge protection is at:
http://www.lightningsafety.com/nlsi_lhm/IEEE_Guide.pdf
- "How to protect your house and its contents from lightning: IEEE guide for surge protection of equipment connected to AC power and communication circuits" published by the IEEE (the IEEE is a major organization of electrical and electronic engineers).
And also:
http://www.eeel.nist.gov/817/pubs/spd-anthology/files/Surges happen!.pdf
- "NIST recommended practice guide: Surges Happen!: how to protect the appliances in your home" published by the US National Institute of Standards and Technology

The IEEE surge guide is aimed at people with some technical background.

A typically destructive surge is hundreds of thousands of joules. Grossly undersized (and expensive) protectors are maybe hundreds of joules. Undersized to be one shot devices. If grossly undersized and fails, then naive consumers will recommend it and buy more.

Nonsense.

The author of the NIST surge guide investigated how much energy can reach a plug-in protector, including the largest power line surge likely (from a very strong lightning strike to a utility pole adjacent to the house). The largest energy at the protector was a surprisingly small 35 joules (and that did not result from the worst surge to the house).

Plug-in protectors with ratings over a thousand joules are readily available.

If using a plug-in protector all interconnected equipment needs to be connected to the same protector. External connections, like coax, also must also go through the protector. As explained in the IEEE surge guide (starting page 30) plug-in protectors work primarily by limiting the voltage from each wire to the ground at the protector. To do that all wires must go through the protector.

Both the IEEE and NIST surge guides say plug-in protectors are effective.

A surge, too tiny to overwhelm protection already inside appliances, may damage a protector.

Nonsense.

So protector circuits must disconnect as fast as possible.

The cheap crap westom buys might. Buy from a major manufacturer.

Leaving a surge still connected to an appliance.

The IEEE surge guide explains the protected load can be connected across the MOVs, and be disconnected with them if they overheat, or can be connected across the incoming wires. If connected across the MOVs the protected load is not exposed if MOVs fail. (Connecting this way is one reason some manufacturers can have protected equipment warranties.)

Sometimes a thermal fuse does not disconnect fast enough. Wires do not burn. Instead the MOV causes a fire.

As the link from GopherT makes clear, UL/ULC 1449 has required disconnects for overheating MOVs for over 15 years.

Even a power strip protector needs protection provided by the other device - with a same name.

Nonsense.

But SquareD says for their "best" service panel protector "electronic equipment may need additional protection by installing plug-in [protectors] at the point of use."

The other 'whole house' solution remains functional even after a direct lightning strike. Protects everything inside the building. Protects from all types of surges.

Service panel protectors are a real good idea.
But from the NIST surge guide:
"Q - Will a surge protector installed at the service entrance be sufficient for the whole house?
A - There are two answers to than question: Yes for one-link appliances [electronic equipment], No for two-link appliances [equipment connected to power AND phone or cable or....]. Since most homes today have some kind of two-link appliances, the prudent answer to the question would be NO - but that does not mean that a surge protector installed at the service entrance is useless."

A service panel protector is likely to protect anything connected only to power wires.

But they do not, by themselves, prevent high voltages from developing between power and phone/cable/... wires. The NIST surge guide suggests most equipment damage is from high voltage between power and signal wires.

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For the original question, connecting protectors together, no manufacturer will recommend that. And UL does not allow it. Use a single protector with high ratings. They are readily available.

And plug-in protectors do not work primarily by grounding spikes (as detailed in the IEEE surge guide starting page 30).

 

Engineer something elaborate that cuts off the power if it goes above or below a threshold. Base something around an LM3914.