Is this considered safe nowadays? - Page 1
Forum section: electronics / general

author: ivaylo
author_rank: Frequent Contributor
timestamp: February 14, 2014, 06:09:52 am
content: So I read the nice discussion here -https://www.eevblog.com/forum/reviews/48'-ebay-power-strips/msg385696/#msg385696and decide to buy one of those for myself. I go to Fry's and pick one of these up -http://www.frys.com/product/5960984(looked exactly the same ashttp://www.frys.com/product/6820336,just different labels). Then I go home, wonder should I trust this thing (it's no eBay junk, right) and open it up. To say I am shocked, no pun intended, is mild. Not only the bare wires in a thinly painted tin box, but they were also bent, almost touching the opposite polarity around a few of the sockets. Is this how these are usually built (never looked inside those long metal ones)? The metal case *is* kinda rigid but I wish they'd put some plastic between those long running bare wires.

author: VK5RC
author_rank: Unknown
timestamp: February 14, 2014, 06:20:23 am
content: Was the metal box earthed (I suspect not)?

author: ivaylo
author_rank: Frequent Contributor
timestamp: February 14, 2014, 06:28:20 am
content: No, it wasn't (at least not in an obvious way). Returned it immediately to the store so can't check now...

author: VK5RC
author_rank: Unknown
timestamp: February 14, 2014, 07:05:13 am
content: A very good move. Even if it is "ok" now later on something might land on the box bend it and zap. Th magic smoke comes out of you!

author: peter.mitchell
author_rank: Super Contributor
timestamp: February 14, 2014, 07:30:44 am
content: Yes, this is fairly standard practice with these strips. This is very good compared to the cheap k-mart plastic ones you buy for $1.Example video.

author: tszaboo
author_rank: Super Contributor
timestamp: February 14, 2014, 07:49:43 am
content: That is an US outlet. It is not safe by default, no matter what the construction is.I was horrified when I saw one in action in real life. Schuko and British <- that is safe.

author: TMM
author_rank: Frequent Contributor
timestamp: February 14, 2014, 08:11:21 am
content: Quote from: peter.mitchell on February 14, 2014, 07:30:44 amThe copper wires in the OP's pics don't seem to be captive in the terminal lugs though. If the solder fatigues you could have a live wire rattling around inside.

author: IanB
author_rank: Super Contributor
timestamp: February 14, 2014, 08:18:12 am
content: Did that power strip from Fry's have a UL listing?If the power strip had a metal enclosure, how could the case not be connected to the ground wire of the power cord?

author: Bored@Work
author_rank: Super Contributor
timestamp: February 14, 2014, 10:27:25 am
content: Quote from: IanB on February 14, 2014, 08:18:12 amIt could if it would be following the regulations for Class II, double insulated devices. Which this contraption doesn't.

author: nihilism
author_rank: Regular Contributor
timestamp: February 14, 2014, 11:30:23 am
content: wowand i thought some of the ones sold in Australia were bad. Hope an au version of that pos doesn't exist.

author: ivaylo
author_rank: Frequent Contributor
timestamp: February 14, 2014, 04:01:04 pm
content: Quotehttp://www.rhino-tek.com/product_details/powerstrip/powerstrip_12outlet.html- straight from the horse's mouth:QuoteDidn't measure if the box was grounded. Wanted to return it before they close for the day. Did I panic there?

author: 440roadrunner
author_rank: Contributor
timestamp: February 14, 2014, 06:56:54 pm
content: In my opinion this is not safe and should not be allowed any sort of UL type approval. I can still well remember a nearly wasted trip to a mountaintop.This was hauling new equipment, newly configured in a radio cabinet with an alleged 'quality' outlet strip bought through a well known supplier. This was a long ride, some 100 mi. round trip over VERY bad sections of almost-a-road.Bear in mind the system in this cabinet had been tested in shop. We get up there, set it up in the small building, and part of the components fail to power up. Long story short, this outlet strip turns out to have used the much hated "push in" spring contact outlets, and one terminal was loose. Worse, these were (against code) daisy-chained from the duplex terminals so there were no spare terminals that could have been used.We managed to stretch one cord to a nearby outlet, and get the equipment working but we were forced to go back some time later to replace the strip and rearrange. This cost the shop literally hundreds of dollars in lost time.These had been daisy chained as below which is illegal, and had no screw terminals, ..........only the spring loaded "push in" ones

author: Kohanbash
author_rank: Regular Contributor
timestamp: February 18, 2014, 10:18:05 pm
content: Quote from: NANDBlog on February 14, 2014, 07:49:43 amYour comment encouraged me to turn to Google, and I found thishttp://crave.cnet.co.uk/gadgets/plug-versus-plug-49303764/It seems that they ranked the US as 1 of 10, while the British got rated 10 out of 10.The article did ignore "modern" US outlets where the two blades are different sizes and there is a circular ground pin, and seemed to take offense at the use of 110V.

author: N2IXK
author_rank: Frequent Contributor
timestamp: February 18, 2014, 10:47:08 pm
content: Quote from: 440roadrunner on February 14, 2014, 06:56:54 pmWhy do you claim that "daisychaining" like that is illegal? It isn't. In fact, that's why receptacles have multiple connections on each side of them, to allow exactly that kind of connection.Now splicing the 2 circuit wires together in the box with a separate pigtail to feed the receptacle is certainly a BETTER way to do it, as a loose connection at the receptacle will only affect that outlet, and not other loads downstream. But the only place that the National Electrical Code REQUIRES this is on multiwire branch circuits, where the neutral conductor is shared between the red and black phase conductors. On an ordinary 2 wire circuit, the daisychain connection meets minimum NEC requirements.The self-locking "push-in" connections are total crap, and should NEVER be used, IMO. The contact area is just too small for a reliable long term connection at a 20A current. But again, they meet the minimum NEC and UL standards, and most electricians will use them because they save time and work OK at least long enough to get paid for the job. I prefer the better grade receptacles which have the rear holes for the wires, but rely on a pressure plate clamped by the screw to make the connection. Saves the time of forming hooks and wrapping around the screws, and gives just as good a contact.

author: Len
author_rank: Frequent Contributor
timestamp: February 19, 2014, 01:02:37 am
content: Quote from: Kohanbash on February 18, 2014, 10:18:05 pmThen the article is BSCompare the scores to the site's domain name (.UK)

author: vk6zgo
author_rank: Super Contributor
timestamp: February 19, 2014, 05:38:10 am
content: Quote from: Kohanbash on February 18, 2014, 10:18:05 pmApparently it was a fairly weak attempt at "satire".They are having a go at Aussies in "answers to comments"-----apparently we don't recognise "irony"!This may be true,---as the Brits have so much more to be ironic about,they would be much more familiar with the concept.

author: ConKbot
author_rank: Super Contributor
timestamp: February 19, 2014, 11:42:31 am
content: Quote from: Kohanbash on February 18, 2014, 10:18:05 pmThey are probably just mad that cell phone chargers are hugeGiven wikipedia's British slant, I'm surprised thathttp://en.wikipedia.org/wiki/AC_power_plugs_and_socketsdoesnt have a picture of a UK plug at the top.

author: Rudane
author_rank: Regular Contributor
timestamp: February 19, 2014, 05:31:03 pm
content: I might be barking up the wrong tree here, but are you sure those copper wires are bare? Many times copper wire is coated, like in inductors and transformers, so that the wire can't short circuit.

author: ivaylo
author_rank: Frequent Contributor
timestamp: February 20, 2014, 05:44:34 am
content: Absolutely bare. That I tested...

author: 440roadrunner
author_rank: Contributor
timestamp: February 20, 2014, 07:25:33 am
content: Quote from: N2IXK on February 18, 2014, 10:47:08 pmYou are probably current, but I was certainly under the impression that daisychaining by using the 4 outlet terminals was not code, maybe local code here, I don't know. This sticks in my mind as "having been made clear." Been a number of years since I was in either HVAC service or installing radio / telco gear.Hell, LOL, when I first started in HVAC service here locally, the only "inspectors" for gas / LP / mechanical was the local LP / gas suppliers.In any case the main thing here was those dammed spring terminals, which should be summarily illegal

author: Monkeh
author_rank: Super Contributor
timestamp: February 20, 2014, 07:53:24 am
content: Nothing wrong with spring terminals. But the US is probably about 30 years behind on technology there.

author: rsjsouza
author_rank: Super Contributor
timestamp: February 21, 2014, 10:58:02 pm
content: In these days I don't consider that power strips sold in retail have good quality - just like you, I open all of them to be sure of their construction. I have been finding that the ugliest ones tend to have better build quality - the super-fancy-colored-rounded-blue-LED ones in general are pretty bad...Also, I don't consider Rhino products as having excellent quality... A while ago I disassembled one of their power supplies onthis threadand found some poor design and assembly...

author: SteveyG
author_rank: Unknown
timestamp: February 22, 2014, 05:24:21 pm
content: Quote from: Monkeh on February 20, 2014, 07:53:24 amAre you the same guy as on DIYnot?

author: IanB
author_rank: Super Contributor
timestamp: February 22, 2014, 05:47:55 pm
content: Quote from: Kohanbash on February 18, 2014, 10:18:05 pmWell, we can't have accuracy where satire is concerned, can we?They also neglected to mention that while the US supply voltage is 120 V (110 V on a bad day), the Japanese supply voltage is only 100 V (and 90 V on a bad day). If 120 V is wimpy, 100 V is positively feeble.

author: Monkeh
author_rank: Super Contributor
timestamp: February 22, 2014, 06:55:34 pm
content: Quote from: SteveyG on February 22, 2014, 05:24:21 pmWhat does it matter?

author: lewis
author_rank: Frequent Contributor
timestamp: February 22, 2014, 08:54:03 pm
content: It's not often I feel a sense of almost turbid patriotism, but the British 13A mains plug is unquestionably the best domestic mains plug in the world. Unquestionably.

author: G7PSK
author_rank: Super Contributor
timestamp: February 23, 2014, 09:42:40 am
content: Quote from: lewis on February 22, 2014, 08:54:03 pmThere wasn't a lot wrong with the 5,10 and 15 amp round pin plugs that we used to have and are still used for stage work and lighting systems in industrial/commercial situations and I believe used in South Africa and some other countries but for some reason Zimbabwe changed to the 13 amp plug in all places where they don't just twist the wires together.

author: SeanB
author_rank: Super Contributor
timestamp: February 23, 2014, 10:51:29 am
content: 15A plug, good for up to 30A for a short while, or until you have an old socket with weak contacts or one of the cheap ones make as far as I can tell out of something that looks like brass but behaves like it is made from compressed horse apples. I have had to remove a few plugs with a hammer and chisel and replace the socket outlet from them welding themselves into a solid charred mass. This was with a 10A load from a kettle.I would have to scan through the car camera footage to see if there are any good shots from travelling through the "Informal settlement" showing the jungle of assorted wire connecting up illegally to power. Some are used as washing lines as well. Bit hard to get good photos as I tend to go through there at 120 plus on the highway.

author: SteveyG
author_rank: Unknown
timestamp: February 23, 2014, 10:54:11 am
content: Quote from: Monkeh on February 22, 2014, 06:55:34 pmQuote from: SeanB on February 23, 2014, 10:51:29 amThe 13A plug will take considerable overcurrent too if the fuse is bypassed, although cheap sockets or plugs don't fare so well.

author: Monkeh
author_rank: Super Contributor
timestamp: February 23, 2014, 11:14:36 am
content: Quote from: SteveyG on February 23, 2014, 10:54:11 amDo I know you?

author: electronics man
author_rank: Frequent Contributor
timestamp: February 23, 2014, 01:43:14 pm
content: One of the great things about the British plug socket is that the contacts are coverd, this cover is opened by the earth pin only, so the chance that someone will stick something that they should into the plug is very slim the only way that could do this is by putting something in the earth socket as well. Even that is difficult as the object must be the right shape. And that is why I am so proud of British plugs.

author: SeanB
author_rank: Super Contributor
timestamp: February 23, 2014, 01:56:00 pm
content: Same with the regular round pin sockets, has been a mandatory item to have a shroud since the 1960's. Only ones that are over 50 years old are unshielded.

author: denelec
author_rank: Regular Contributor
timestamp: February 23, 2014, 02:57:42 pm
content: The 120/240V system we have in the US and Canada is much safer then the 240V system used elsewhere.Even in our 240V appliances (cooking range, clothes dryer,...), we never have more than 120V line to ground.And you must also consider the fact that the resistance of the human body decrease with voltage (http://en.wikipedia.org/wiki/Electric_shock]http://en.wikipedia.org/wiki/Electric_shock). It's the current that kills you, not the voltage.But I agree that the British plug is safer.

author: SteveyG
author_rank: Unknown
timestamp: February 23, 2014, 03:06:27 pm
content: Quote from: denelec on February 23, 2014, 02:57:42 pmActually it's not. It's the energy that dictates how lethal an electric shock is. You can survive many kA through the body easily...

author: denelec
author_rank: Regular Contributor
timestamp: February 23, 2014, 03:15:19 pm
content: Quote from: SteveyG on February 23, 2014, 03:06:27 pmYou're right, it's the energy that matters. Many kA maybe, but not for long.There is a formula for the maximum current the body can tolerate; I=k/sqr(t) where k=157 for a 70kg person and t=time in secondshttp://www.hubbellpowersystems.com/literature/encyclopedia-grounding/pdfs/07-0801-02.pdf

author: ciccio
author_rank: Frequent Contributor
timestamp: February 23, 2014, 03:57:27 pm
content: Quote from: lewis on February 22, 2014, 08:54:03 pmI cannot agree: it's big, heavy, and the internal fuse's dimensions makes it unobtanium outside UK. When used with a removable power cord, the fuse will protect the plug, not the equipment, and if somebody exchanges the cable with the one from another equipment the fuse will be of no utility.The good thing is that it is polarized.Quote from: electronics man on February 23, 2014, 01:43:14 pmPlease allow me a shot of patriotism (we Italians are low on this, in these times...) : the socket with shutter was first patented in 1968 by the Italian company VIMAR (under the commercial name SICURY), and after a short time they made the design of public domain, releasing all their patent's rights.http://www.vimar.com/en/int/the-quest-for-safety-1064122.htmlBest regards

author: Monkeh
author_rank: Super Contributor
timestamp: February 23, 2014, 04:04:34 pm
content: Quote from: ciccio on February 23, 2014, 03:57:27 pmIt will protect the cable, not the plug, not the equipment. The equipment has to protect itself.QuoteIt will be of perfect utility, because it's there to protect the cable. If the equipment has a detachable cable, it is very much up to it to protect itself!QuoteAnd BS1363 was written with shutters from the beginning. In 1947. Sorry.

author: SteveyG
author_rank: Unknown
timestamp: February 23, 2014, 04:05:21 pm
content: Quote from: ciccio on February 23, 2014, 03:57:27 pmBut then the connector and cable is always sized to the load. You would never have, say a Fig8 connector on something rated greater than 5A and a Fig8 connector is always fitted with 0.75mm or greater cable. Similarly, something with an IEC connector would be suitable up to 10A and the cable is always rated greater than this.Equipment is always protected internally to gain certification over here. The fuse in the plug is only designed to protect the appliance lead not the appliance.

author: electronics man
author_rank: Frequent Contributor
timestamp: February 23, 2014, 04:15:25 pm
content: Yeah lots of thing are double fused in the uk, one in the plug and one in the product

author: ciccio
author_rank: Frequent Contributor
timestamp: February 23, 2014, 04:17:45 pm
content: Quote from: Monkeh on February 23, 2014, 04:04:34 pmTouché... you're right.

author: AmericanLocomotive
author_rank: Contributor
timestamp: February 23, 2014, 08:23:07 pm
content: Quote from: electronics man on February 23, 2014, 04:15:25 pmMainly because the goofy British ring-circuits can deliver far more current than the outlet (32 amps typically), cord, plug or equipment could handle. This requires the cords/plugs to be fused to protect themselves.The rest of the sane-world only uses branch/radial circuits where the circuit-breaker cannot deliver any more current than any one outlet is rated for.

author: SeanB
author_rank: Super Contributor
timestamp: February 23, 2014, 08:37:08 pm
content: 20A here is not far off, more than most cables can withstand as well. Not helped by Mr OHL cutting costs and making the copper core thinner every cycle, or even leaving the copper out all together and using aluminium or steel wire instead. You get cables nominally 1.5mm where the 2 power cores are more like 1mm and the protective earth is more like 0.75mm. Still the insulation is a lot thicker, they will pass a 5kV insulation test with no problem, though they might glow as bright as a 2 bar heater if you plug a 2kW load into them.

author: Zero999
author_rank: Super Contributor
timestamp: February 23, 2014, 09:45:08 pm
content: Quote from: AmericanLocomotive on February 23, 2014, 08:23:07 pmThat makes sense to me. Having the fuse in the plug means if there's a fault, it won't take out all of the other appliances on the same breaker. It's also good because the fuse can suit the cable: 3A, 5A or 13A.Or do you have one breaker per outlet? That's a hell of a lot of breakers.

author: SteveyG
author_rank: Unknown
timestamp: February 23, 2014, 10:03:45 pm
content: Quote from: AmericanLocomotive on February 23, 2014, 08:23:07 pmI think you'll find radial circuits are also used. Totally depends on the installation and requirements. There is only an RFC on the upstairs of our house, the rest are radials.

author: AmericanLocomotive
author_rank: Contributor
timestamp: February 24, 2014, 01:08:28 am
content: Quote from: Hero999 on February 23, 2014, 09:45:08 pmIn the US, we use branch/radial circuits exclusively. You can have as many devices as you want on one breaker. Typically you'd have all the outlets in one room on one circuit. Bigger rooms (or rooms with high electricity demands) will have 2, 3 or even more circuits for the outlets. Several different rooms will generally be on one lighting circuit.As far as protecting the cable: Either the device it self is fused if it has the possibility of drawing more current than the cable can handle continuously, or the cable is of a heavy enough gauge that if it shorts, it'll instantly trip the breaker. Even a 20 gauge wire (0.52mm^2) can flow enough current in a short-circuit situation to trip the branch breaker. You don't usually find things in the US with cords thinner than 20 gauge. Even something like a desk lamp will usually have 18 gauge/0.824mm^2 wire.

author: IanB
author_rank: Super Contributor
timestamp: February 24, 2014, 01:51:00 am
content: Quote from: AmericanLocomotive on February 24, 2014, 01:08:28 amNice in theory, but may not always work out in practice. How about 16 duplex sockets and 6 fixed lights all on one 15 A circuit serving four rooms? The electrical arrangements in my house were done by some crazy dude with a scrambled brain.

author: AmericanLocomotive
author_rank: Contributor
timestamp: February 24, 2014, 02:49:26 am
content: Quote from: IanB on February 24, 2014, 01:51:00 amThat's technically not illegal (unless in a commercial/industrial setting, in which case it is). For residential stuff, the NEC generally recommends goes by 10 outlets (a light fixture is considered an outlet) for a 15 amp circuit, and 13 outlets for a 20 amp.

author: N2IXK
author_rank: Frequent Contributor
timestamp: February 24, 2014, 03:22:06 am
content: The problem with too many receptacles and outlets on a branch circuit is a DESIGN issue, not a safety issue. And the National Electrical Code specifically states that it is a safety code , NOT a design manual. Having an entire floor on a single branch circuit is certainly a pain in the ass, would drive most folks crazy, and subsequent NEC revisions and added requirements over the years make it pretty much impossible to do in NEW construction. But it isn't really a SAFETY issue, assuming that the single 15A branch circuit is properly installed.Stuff like this is VERY common in older homes that have been added onto over the years. For many years, the typical service to a residence was 60A, feeding a fusebox with 4x15 A fuses in it. Many times I have seen the old fusebox replaced with a circuit breaker panel, but branch circuits not separated or updated in any way, with perhaps the addition of a few new dedicated circuits for window A/C units, etc.The oldest residential wiring in the world is in the US, and some of the original open wire "knob and tube" stuff is still in service today. The original practice in wiring a house was a single bulb socket in the middle of each room ceiling, and maybe 1 receptacle outlet per large room (some folks just used adapters and tapped the lamp socket to run a fan or radio or whatever). Many of the property owners in the US would never stand for having their local building authority REQUIRE periodic updating and safety inspection of old wiring. In some cases, insurance companies can apply pressure to make upgrades in the form of higher premiums or non-renewal of policies for really dilapidated wiring, but this is rare, and usually only happens when a building is sold, and the new buyer's insurance company insists on it.

author: Monkeh
author_rank: Super Contributor
timestamp: February 24, 2014, 04:00:26 pm
content: Quote from: AmericanLocomotive on February 24, 2014, 01:08:28 amNeither provision protects the cable from damage to the cable not resulting in a hard short.Also, never assume a short circuit will cause a breaker to operate, you must consider the fault loop impedance.