I want to buy surge protected socket however these products generally has 1.5-2 meters long cable but it isn't enough for me. On socket there is a warning:

"Plug in this product directly to.wall plug and do not use any other extension sockets in a row."

In this warning last sentence confused me. I need 4-5 meters long, therefore I'm thinking about plug in typical triplet sockets to wall plug and then using surge protected sockets. Is it appropriate use?


We just had the Fire Marshall visit our business and give us a fire inspection.

We got wrote up for several things.

  • Extension cords are for temporary use. If you need power at a remote point, get an electrician in and extend an existing circuit or run a new circuit.
  • No Zip-Cord type extension cords to be used, Ever!! They don't have abrasion resistance like SJO type cord. Laying over a sharp edge can cause cold flow of the insulation and they cannot withstand being kinked or having sharp objects dropped on them. Plus the insulation can age and crack.
  • If you must extend the number of power sockets (multiple outlet tap), it must have an internal circuit breaker.
  • If you must have a permanent extension to bring power to a remote area, use a power strip with an internal circuit breaker and appropriate length SJO type cord (3', 6', 10', 15', 20', 25').
  • Never chain power strips, they are available with different length cords (to reiterate).
  • Any UPS installation shall either be plugged directly into the wall socket or an appropriately rated power strip with internal circuit breaker.

Note: You probably won't find the long cord power strips locally, I would try online for the country appropriate type you need. Industrial/Commercial applications or Server applications tend to have the longer cords.

Zip Cord Multi-outlet Extension Cord - No Circuit Breaker, No Outer Jacket on cable (arrow to best view). In the US, this is referred to as Zip Cord as the grooves in the insulation allow for the different conductors to be Zipped apart for termination. The insulation will tear along the groove. The insulation is soft, easily penetrated and abraded, and with age, can crack and expose conductors. It is also easily kinked which can break the inner conductor leading to a high resistance fusible fire starter which is also why there is a US code requirement for Arc Fault circuit breakers to be used on rooms where corded lamps are likely to be used now. AKA Lamp Cord.

Zip Cord Extension

Jacketed SJO Cord - SJO style cord with individual conductors, fiber filler and protective outer jacket which also may unfortunately be referred to as zip cord as it can have an internal string to allow cutting the outer jacket when pulled to expose the inner conductors.

SJO Cord - Jacketed

  • 2
    Can you provide a picture of a zip-cord type extension cord, for reference?
    – MDMoore313
    Apr 30 '14 at 15:51
  • @BigHomie - Done! Apr 30 '14 at 16:13

The devices have that warning because of safety concerns, not surge concerns. Having extensions plugged into extensions creates a slightly higher risk of fire/sparks because of a larger number of connections. Also, it is very easy to overload the circuit (since you now have so many outlets). Be careful to match the ampacity rating of your power strip to that of the extension cord. Extension cords will be labeled with the maximum current they can support. In my undergraduate dorms, we would fail our monthly safety inspections if we had any cases of power strips being plugged into other power strips or extension cords.

For surge protection, it's desirable to have the protection (SPD) as close as possible to the device being protected. From that point of view, you should plug your SPD into the extension cord. One you have the point-of-use SPD, you may want to install a "whole-house" SPD in your main circuit breaker or in subpanels.

Alternatives include buying a power strip with a longer cord (I see 15 and 25 foot models available online) or installing a new power outlet closer to where you need it.

  • thank you for your response. I can't install new power outlet, and i couldn't find longer cords for SPDs. Maximum 2 meters. So , i don't misunderstood you, i should plug standart extension to wall outlet and plug SPD to this standart extension, right? So why there is a warning You have to plug this protector to wall outlet ?
    – Eray
    Apr 27 '14 at 16:36
  • 1
    The cord on the SPD the OP links is rated for the 15A, so I wouldn't recommend plugging it into anything other than an outlet or extension cord rated at 15A. The warning is related to the rated capacity of the cord. I've had to briefly run an air compressor a couple of times on an extension cord that was too long when I ran out of hose, and it noticeably heats the extension cord. Note that this also has "surge concerns" - you might end up dumping an over-current back through the ground, also through the extension cord.
    – Comintern
    Apr 27 '14 at 16:46

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