There is always one power strip in every home. In addition to the number of plugs that can be plugged in, there are several important points to consider, such as longevity, lightning protection, and dust prevention shutters. To ensure safe and convenient use, choose with care!
- Law on the manufacture of power strips
- Cord life
- Prepare for possible accidents.
- Includes recommended products!
- Supplement: To prevent other accidents
Click on the table of contents to jump.
Law on the manufacture of power strips
It is not enough for a power strip to be able to conduct electric current; there are standards set by law that must be met before it can be manufactured. This is the "Electrical Appliance and Material Safety Law," which was revised after 255 accidents (175 cases of misuse by consumers) occurred in the past 10 years since March 1, 2010.
Specifically, the following details are stipulated
Fixed Ratings
- Current rating of extension cord set is 15A or 20A
- Voltage rating of extension cord set is 125V or 250V
limited availability of wires
- Electric wires are limited to cabtyre cords or cords with protective sheathing
This means that they are covered with a safe material to prevent electric shock.
Provisions for Insulation Materials for Wire Integral Molded-In Plugs
Plug tracking resistance
- The outer surface of the plug on the butt face of the outlet, where it contacts the plug blade, shall have a PTI of 400 or greater.
Flame resistance of plugs
- The insulating material holding the plug blades together shall conform to the glow wire combustion test at the test temperature: 850°C. Or, glow wire ignition temperature: 875°C level or higher.
- If the plug has a one-piece molded PVC resin outline, a thermosetting resin shall be used for retention between the plug blades.
A plug blade is the two pieces of metal we pull out or insert. The insulation and flame resistance of the materials in contact with these metals are defined.
Other requirements include testing obligations.
Revision of Electrical Appliance and Material Safety Law (Revised on January 13, 2012)
In conclusion, we find that what is on the market is
- Withstand excessive currents and voltages to some extent.
- It is covered with a sufficiently secure film.
Cord life
The above law indicates that every power strip is safe at the point of manufacture. However, the entity is still just an elastic vinyl material. It will harden and crack over time. So how long exactly can they be used safely?
The following was written on the website of Hashimoto Kosan Corporation, a manufacturer of cab tire cords, which are cords used in power strips and electrical appliances.
The lifespan of a cabtyre cable is 10 ~ 20 years, depending on the application, manufacturer, and usage. In practice, however, there is no definite lifespan for cabtyre cables.
For this reason, some companies replace cab tire cables on a regular basis. This is to prevent the plant from shutting down due to aging cab tire cables, which would disrupt the production system.
What is the life span and service life of cabtyre cables? | Hashimoto Kosan
It is surprisingly long-lasting. However, as it says there is no clear standard, it depends on what kind of treatment is being done. Also, the life expectancy described here is the true life expectancy, so considering safety and price, we recommend replacing them in less than 10 years.
Prepare for possible accidents.
As electrical appliances, there are accidents that can occur in any home, but there are two accidents that can be reduced in likelihood by choosing a power strip with specific features. (Accidents caused by the way they are handled are discussed in the last chapter.)
1: Tracking phenomenon
Leaving a plug plug in an outlet for a long period of time causes dust to accumulate between the outlet and the plug. When the dust accumulates and becomes damp, it can be ignited by the electricity flowing through it. This phenomenon is called tracking. Tracking occurs only when a plug is plugged into an outlet, and it does not matter whether the appliance is in use or not, or whether the power is on or not.
The following video was uploaded to YouTube by the National Institute of Technology and Evaluation (NITE) and shows an ignition caused by the tracking phenomenon.
2: Lightning surge
Regarding lightning surges, let me quote from Sanwa Supply's explanation.
What is lightning surge?
Harmful overvoltages and overcurrents that occur momentarily on high objects such as power lines during lightning strikes.
This surge voltage enters the house through telephone lines, power lines, antennas, and the atmosphere, and this surge voltage causes electronic equipment such as PCs and routers to suffer from insulation breakdown, malfunction, and deterioration. The "Lightning Guard" is the best lightning surge countermeasure because its built-in absorbing element (varistor) absorbs lightning surges to prevent malfunctions of connected PCs and other equipment.
Countermeasures against Damage to Personal Computers Caused by Lightning Strikes | Sanwa Supply Co.
From the above, it can be seen that in addition to the legal requirements, the following two measures are necessary
- Dust ingress countermeasures
- Lightning surge protection
Caps to prevent dust from entering are also available at 100 yen stores. However, be careful when using them, as they can break off inside and become impossible to remove as they deteriorate.
Includes recommended products!
Now, based on what we have found out so far, we recommend each of the following two types of power strips.
- Type with extension cord
- Direct mounting type
There is also a vertical, desk-mounted type of power strip called a tower type. While convenient and easily accessible, they look cluttered on the desk, take up less space with power strips and cords, and tend to accumulate dust and other debris. Therefore, we recommend attaching a rack for power strips under the desk and fixing them in a suspended position.
Garage wire cable trays range from 39.7 cm (S) to 88.7 cm (LL), but the S is sufficient for a power strip with about six connections.
Type with extension cord
There do not seem to be any manufacturers other than Sanwa Supply and Elecom that produce power strips of the type with extension cords that meet both of the aforementioned requirements.
Sanwa Supply: TAP-S18-2 (4,280 yen)
In addition to dust prevention shutters and lightning surges, individual switches and swing plugs make this a truly versatile product!
Elecom: T-K6A-2625 (2,051 yen)
In addition to the same features as Sanwa Supply, it features the following
- The switch must glow.
- Must be available in two colors: white and black.
As for switches, there are those who prefer products that glow or those who prefer products that do not glow. Both meet basic safety standards, so please choose according to your preference. Personally, I recommend the Elecom one because it is easier to tell whether the power is on or off if the switch glows.
Direct mounting type
This type did not have a dust-proof shutter, perhaps because the insert does not face up.
Sanwa Supply
ELECOM
Supplement: To prevent other accidents
Tracking phenomena and lightning surge accidents were discussed earlier. However, there are other accidents that can occur, so be aware of them.
1: Ignition of bundled cords
If a large current is applied while the cords are bundled, the core wire in the cord may break, resulting in abnormal heat generation and risk of ignition. Please pay attention to the maximum power consumption (up to 1500W per typical outlet) and use unbundled cords. In addition, avoid using power strips for electrical appliances with large power consumption as much as possible.
NITE calls for attention to power cord ignition accidents, which occur frequently in winter.
2: Ignition with deformed plug
Continued use of a deformed power plug by forcing it in may cause abnormal heat generation due to poor contact.
3: Tracking phenomenon caused by alcohol or diluted detergent on the power strip
Spraying alcohol or diluted detergent on power strips may cause tracking and risk ignition. Clean power strips by wiping them dry, and do not wipe them with cleaning solutions.
Of course, please note that twisting, placing a heavy object on top, or pulling may also cause the wire to break, resulting in abnormal heat generation and ignition. We hope the above information will be helpful.
