Multiple Power Strips Connected In Series

There's really no reason not to. If they all have circuit breakers, which most do, the upstream guys will trip if they're overloaded by the total load. If you put the lighter loads towards the end of the string, voltage drop along the total length of power cord will be minimized. As far as length goes, it's not much different from a long extension cord.

John

Hi,

One reason is due to the fast rise of current in transients the inductance of the added length of wire defeats the transprotection. One inch of wire ( type used in the power strips ) is about 19nh. if you add the 1000 amps possible and the length of wire at a high di/dt then many volts can be generated and addition the phone leadin may have lower impedance ( more current ) than the power leads due to the transmission line effect of the telephone line.

Ray

Here's what I found in groups:

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Putting power strips in series only degrades their performance.

Someone wires 5 power strips in series and you're at the end.

- Multiple AC power strips in series.

"Does 5 power strips in series violate some kind of NEC code or ordinance"?

{Dialog where a power strip is diagnosed as a problem}

Check for interference? Electrical appliances on the same circuit or operating near the computer can cause interference. Other causes of interference: power extension cables, too many devices on a power strip, or multiple power strips connected to the same electrical outlet.

OPNAV INSTRUCTION 5100.19D VOLUME II CHANGE TRANSMITTAL 1 30 AUGUST

s. Use onlt Navy-approved power strips for computer equipment, printers, and peripherals. Never use power strips in series (connected to one another).

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I see no hard evidence one way or the other at this point.

Most computers have switching power supplies, is there any evidence that the combination of line filters and or surge suppressors adversely affects them?

I have seen UPS devices have problems if they are fed anything but current streight from the wall socket. They detect a small flux in the supply as intercepted by the power strip and switch into battery mode.

I'm beginning to think that this has all the makings of an urban legend. Maybe it is time to contact MythBusters.

Here's another source:

From "Coordination: 1980" - F.D. Martzloff

Fact 3. Without substantial connected loads in the system, the open-circuit surges appearing at the service entrance propagate along the branch circuits with very little attenuation.

Conclusion 4. Coordination of surge suppressors requires a finite impedance to separate the two devices, enabling the lower voltage device to perform its voltage-clamping function while the higher voltage device performs the energy-diverting function.

Conclusion 5. The concept that surge voltages decrease from the service entrance to the outlets is misleading for a lightly loaded System. Rather, the protection scheme must be based on the propagation of unattenuated voltages

Conclusion 6. Indiscriminate application of surge protectors may, at best, fail to provide the intended protection and, at worst, cause disruptive operation of the suppressors. What is needed is a coordinated approach based on the recognition of the essential factors governing devices and surge propagation.

There is a wealth of papers concerning surge suppression available tn the directory of the example above, that I am trying to sort through.

More Later [YMMV]

What does a surge seek? Destructive transients are typically longitudinal mode. IOW they seek earth ground. If not earthed at the building entrance, then they will seek earth ground destructively through household appliances. Too many fail to learn of multiple types of transients. The destructive transient is not stopped, blocked, or absorbed. And yet that is what a plug-in protector must do. Is that plug-in protector going to stop what miles of sky could not?

Introduction to protection principles in "Pull the wall plug or not?" in nz.comp on 7 Sept 2004 at

For more technical sources, then three consecutive posts: " Belkin Surgemaster worth the money?" in the newsgroup uk.comp.homebuilt on 29 Sept 2004 at

Surge protection demonstrated by a simple example: "Whole house surge suppressors" in alt.home.repair on 12 Jul

Transients first form a complete electrical path from cloud to earth. Only after current is passing through everything, then something in that path fails. Destructive transients seek earth ground. Earthing - and not some protector - defines a protection 'system'. A surge protector is only as effective as its earth ground. Too many forget about essential earthing and instead hope what they see on retail shelves is actually protection. No earth ground means no effective protection.

Sean wrote: