Almost burned my shop down and didn't even know it

[SmithDoor]

As far as fuses vs circuit breakers, I am firmly in the circuit-breaker-only camp.

In industry, where 3-phases are used, you never want to trip off only one phase to motors and such, and so many industries outlaw fuses except in special circumstances.

In residential use, fuses are fine, but are not renewable, and so you have to stock a supply of every size.

You may get slightly better protection with a fuse in some circumstances, but a fuse does not necessarily offer better overcurrent protection than a circuit breaker.

A circuit breaker is comprised of two components, which is an instantaneous-trip magnetic coil, and a thermal element that heats up over time to trip a breaker.
The idea is for a large short circuit, the magnetic portion of the breaker will trip it instantly.

For an overcurrent, which is not a short circuit, but rather a slight excess current above the breaker rating, the breaker is designed to not trip immediately, since it takes time for the bimetalic element to heat up and trip, so that motor staring surges or other temporary surges will not trip a breaker.

.

Time delay fuses can very helpful with motors and stick welders. There rated about 3 to 5 times for 10 to 20 seconds for motors or welders to start.
Breakers will trip at a lot lower amps.

Dave

 

[GreenTwin]

Neither motors or welders should take anywhere near a 10-20 second starting surge, but I get your point.

Induction motor starting surge is typically 6 times the motor full load current, but for a very short period of time.

Transformers (which is what a typical stick welder is) I think typically have a 12 times inrush for a short period of time.

I have never tripped a single-phase motor breaker on startup using the NEC recommended breaker size, and have never tripped my welder on its 50 ampere breaker either on startup.
I have tripped my welder 50 ampere breaker on its longtime overload setting when welding for a long time at a high amperage.

Industrial breakers have time setting dials to avoid nuisance trips, but residential breakers don't have adjustable trip curves.

Perhaps fuses would be good for special applications, but for run-of-the-mill shop use, a breaker should work fine if properly sized with most load types.

.

 

[Richard Hed]

I' m just happy to have read all this stuff about electrical wiring, as I am about to wire a 2HP motor in my garage. I tsry to keep to the sensible methods but there are some items here I never knew about. Thanx to all!

 

[william_b_noble]

The shock hazard of 240v is higher than 120, the potential for arc-over wit degraded insulation and water is also greater. And 220v plugs in the UK have integral fuses, at least the ones I have.

 

[GreenTwin]

The thing is, the US already has 240 volt single phase in almost every house.
I have 240 volt receptacles for window units all over my house, and there is nothing unsafe about them.
Each is protected by its own dedicated circuit breaker.
They are not fused, and don't need to be.

We could use the same wiring (assuming you have modern Romex-style wiring in your house), and just replace the receptacles, and reconnect the wiring in the panel across two poles of a 2-pole circuit breaker.

You really don't get into arc-over problems until you get above 5,000 volts.
Above 5,000 volts, I have seen the air get ionized by dust particles, or something else in the air, and then you can get a huge flashover with a 30,000 F arc.

If you have degraded wiring insulation in your home, you really need to rewire your house with modern Romex-style wiring.
Typical hardware store Romex copper wiring is rated for 600 volts, but I would probably not use it above a nominal 300 volts or so, just to be on the safe side.

A relative of mine bought a house a few years ago, and it was built in the early 1950's, and had early Romex-style copper wiring, but the insulation cracked and fell off if the conductor was bent or moved.
They did a complete rewire, and now the house is safe with modern wiring, receptacles, lighting, and a new panelboard and service entrance.
As I mentioned before, no amount of savings is worth a burned down house.

If you don't get anything else in a house right, get your wiring right.

There are several trends these days in residential electrical systems.

One is using personnel ground fault protection for and receptacle that is within about 6 feet of water, such as a sink.
The ground fault receptacles work very well, and I use them not only at sinks, but I use modular plug-in ground fault units all around the house and shop (like a very short extension cord with a ground fault unit in it).

A 120 VAC ground fault receptacle measures the difference in current between the neutral and the energized conductor, and if the current differential is greater than 10 milliamps, the circuit is opened by the ground fault receptacle.

10 milliamps is the magical number below which you are safe from heart ventrical fibrilation, which is what kills the most people due to electrical faults. Higher voltages act like a defibrilator and contract the heart muscles violently, and then the heart starts beating again usually.

120 volt shocks that are above 10 milliamps cause ventrical fibrilation, which is irregular spasms of the heart muscles, and the heart does not pump blood with it is fibrilating.

The way they stop fibrilation is with a high-voltage de-fibrilator.

I work around a lot of 5,000 volt motors and associated switchgear, and I consider that relatively safe gear and a relatively safe voltage.

I also work around 23,000 volt switchgear, and I am very wary of that, and have seen coworkers have some near misses from unintentional 23,000 volt arc flashes caused just by opening the front door of the switchgear.
The arc flash out of the front of a 23,000 volt switchgear cubical is about 10 feet long, and not something you really ever want to witness in person.

I had to add on to a 35,000 volt outdoor substation at a steel mill, and that was pretty scary stuff, with exposed aluminum tubes for conductors. The service came in from the utility company at 161,000 volts, which is really some wild looking switchgear and breakers.

.

 

[GreenTwin]

The other trend in residental wiring in the US is the requirement for arc-flash style circuit breakers on some circuits.

Arc flash breakers can save your house, especially with a low current arcing fault.
Arcing faults can be high impedance, and so while the fault is arcing (such as the photos above at the beginning of this thread), the current produced by this fault is often lower than the trip rating of the circuit breaker, and so the breaker does not trip until it becomes a huge fault, and often with lots of fire.

Arc flash breakers can sense the arcing, and open the breaker before significant damage has been done.
I am not convinced that arc flash breakers are refined enough for general use without excessive nuisance trips (I have not tried one yet), but that is the coming trend, and I think US Code requires them in certain places in a residence.

.

 

[GreenTwin]

My crafty next door neighbor puts out about 1,000 xmas lights every year, and originally she connected all of her outdoor circuits to ground fault breakers, but when it would rain, the light circuits would trip the ground fault units.

Her solution was to remove all ground fault devices from all of her circuits, which is an incredibly dangerous thing to do, but you can't argue with stupid, and she says "Well it works doesn't it ?".

And I say "Yes it works, but you can also fix a blown fuse by inserting a coin into the fuse holder, but no sane person would do that either.
There is no faster way to burn a house down than to put a coin in a fuse holder, but it use to occur all the time prior to the common use of circuit breakers in residential panelboards.

.

 

[Robsmith]

A few more comments on electrical things.

The members on the board that writes the National Electrical Code for the US is comprised of people from various backgrounds, such as manufacturers and installers, and each has input into the NEC.

The manufacturers want to sell products that maximize their profit.
The installers want products that are easiest and quickest to install, again to maximize profit.
The other folks mainly want to prevent the electrical systems from burning up.

Its like Ralph Nader said about the Corvair, it is unsafe at any speed.
Likewise, the push-in connectors on receptacles are a Corvair-type affair, and they should never be used for any reason.
The fact that there are push-in options on receptacles just means that they were allowed by Code for various folks to maximize their profits.

The spring on the push-in is very small, and the contact area is also small.
The spring can weaken over time, and with a little oxidation of the copper, the joint will become unsafe, especially at any significant load.

Studies have shown that a screwed copper joint will stay tight indefinitely (unlike a screwed joint with aluminum wiring).
In the process of tightening the screw, the oxides on the copper wire are scrapped off, thus providing a very low impedance joint that operates at a low temperature.
The area of a screwed connection is far more than the area of a push-in connection, and the force on the conductor with a screw remains indefinitely tight.

Aluminum wiring tends to creep, ie: it flows when pressure is applied, and so a screwed joint with an aluminum wire must be re-tightened every so often.
The oxides on an aluminum wire are much worse than on a copper wire, and without cleaning the aluminum wire and immediately applying de-oxidation compound, the oxides in an aluminum wire joint will overheat the wire due to high impedance.

Aluminum wiring for residential use is like the Ralph Nader Corvair; unsafe at any speed.
I have seen the very best modern aluminum conductors installed under the most stringent conditions in industry fail and burn up large distribution panels.
Don't use aluminum wiring for anything, and don't believe the sales pitch about residential aluminum wiring being safe (it is not).

Aluminum wiring is used extensively in medium voltage utility company power distribution, but this is a different animal operated a a much higher voltage, and terminated by a professional lineman.

I don't believe a combination receptacle and switch is more safe than just a receptacle, and in fact I think it is less safe, because you have to worry about worn switch contacts and worn receptacles contacts, and so two points of failure instead of one.

I think the reason that the 240 volt receptacle circuits can be more safe is that the amperage for any given load is 1/2 that of a 120 volt circuit. The heat generated in the joint of a receptacle is (I squared R), where I is the current in the circuit, and R is the resistance of the joint.
If you reduce the current by 1/2, you also reduce the heat produced by the receptacle or connection joint by 1/2.

I would guess that 90% of the receptacle branch circuit failures in the US are caused by poor connections, especially push-in connections, and worn contacts on receptacles and plugs.

If you plug a small cord (say a #16, or even a #14 AWG) into a 15 or 20 ampere receptacle, and draw more current than that that cord can safely dissipate, you will melt the cord and probably the receptacle.

Almost all 120 volt plugs on almost all commercial equipment are the 15 ampere style, and 12 amperes is about the most you can pull through them when conditions are idea; ie: the plug and receptacle are not worn.

I really never seen any 20 ampere 120 volt plugs used, except perhaps in some special industrial setting.

I do recommend using 20 ampere receptacles and switches in a residential setting, to give an additional margin of safety as far as current capacity, but you have to watch the Code requirements on that, since some codes assume a 20 ampere receptacle will have a 20 ampere load on them, which is false.

.

The AS/NZS WIRING RULES. Australian Standards/New Zealand Standards 3000 were originally written by an insurance company. Resulting in a very complicated and detailed set of rules and standards. Hence the requirements for a workshop are very detailed and specific. It's all based on a "cover your arse" and you won't get sued. ha ha ha

 

[terryd]

SCARY PICTURES


Years ago I had my 1 HP lathe plugged into a nice safe 20 amp circuit in my shop. Some things were piled in front of the outlet so I couldn't see the plug. I was doing some long periods of heavy work on the lathe for several nights. Never gave it a second thought. Then, maybe a week later, I was cleaning up and moved the stuff from in front of the outlet where the lathe was plugged in.
What I saw scared the pee out of me.

I am attaching all the pics of what could have been a real disaster.

View attachment 139927View attachment 139928View attachment 139929View attachment 139930View attachment 139931

Hi Lloyd,

You're lucky, here was mine:

Fortunately I had excellent but expensive insurance which covered all of my losses. \lesson? Check your insurance for cover limits - mine had no limit up to £1,500,000,

TerryD

 

[JLaning427]

Wow, this has been a wide ranging electrical discussion. And a couple of you guys have had some extensive experiences, some I'd like not to share (like Terry's garage fire)

I'm not sure whether I can pick a winner on the fuse vs cb discussion. Fuses certainly have their place, but they can be sized incorrectly by whomever is doing the repair. Taking a blown 5 amp out and putting a 20 amp in its place doesn't do to many good things, except put the equipment back into service (for a little while).

But on the other side of the coin, cb's do need to be exercised at some frequency, or they may fail to trip. One of the places I used to work, the 800A main breaker welded itself closed over the years. We didn't find out about it until we tried to turn it off to do an upgrade and couldn't. Had to have the utility company disconnect the transformer to de-energize. That could have been a bad day.

Most people don't know you're only supposed to load a branch circuit to 80% capacity (either 12A on a 15 or 16A on a 20). Some kitchens have just one circuit, and we all have microwaves, toasters, crock pots, instant pots, air fryers, electric skillets, 12 cell phones, and a bunch of other stuff plugged into it. It's a miracle more kitchen don't catch fire. I guess we get lucky there.

I personally dislike the back stab wiring method. It is easy, but I don't think it is as good at transferring power as screw terminals, at least when properly installed. But maybe there is a place for it, because I've seen screw terminals with the wire "hook" running the wrong direction.

The melted plastic box in the original post is a bit of an eye opener. Homebuilders use plastic boxes all the time, probably because they are lower cost and faster to install. (Good, fast, cheap, pick 2). I wonder how a steel box would have looked in this situation? Would it have gotten hot enough to start a fire? Doubtful, but I've been surprised by other events.

James

 

[Lloyd-ss]

Hi Lloyd,

You're lucky, here was mine:

View attachment 139995

Fortunately I had excellent but expensive insurance which covered all of my losses. \lesson? Check your insurance for cover limits - mine had no limit up to £1,500,000,

TerryD

Crapola Terry. What a heart breaker.

 

[nealeb]

One of the advantages of the UK house wiring system is that there is generally a "ring main" which daisy-chains all the sockets and back to the consumer unit (box with RCCDs/MCBs etc). The cable used (2.5sq mm) is nominally good for 20A, but fed via a 30A MCB. But then, in effect, each wall socket is fed via two 20A cables. BTW, all backing boxes must be earthed and even if they are plastic, there will be a spare terminal fixed to it for the earth pigtail. Not entirely sure why, but there we are! However, all plugs are fused as someone has mentioned. The plugs are often moulded on to cables these days but the fuses are replaceable. Common ratings are 13A, 5A, and 3A. You cannot (without actually bodging something) even plug a multi-way extension socket (quite often used) except by way of the 13A plug so the total consumption however many appliances plugged into it is limited. It is possible to include "spur" connections - a socket fed by a single 20A cable typically from the back of an existing socket. I'm never happy with the way you have to force three fairly heavy solid copper wires into a single terminal with a screw-down fixing as I cannot see how you guarantee that all cores are well-clamped but that's the way it's been done for years.

I had some wiring work done a while back and a junction box with multiple connections needed to be replaced. Although I fitted a removable access panel later, it was originally going to be hidden behind a plasterboard ceiling and the electrician used Wago spring-loaded connectors as he said that in hidden spaces, screw-down terminals were subject to loosening over time. I have no data on this at all but it was an interesting and reasonable-sounding idea - and it has the advantage that you have one copper core per spring-loaded connector (not "push-fit" as you have to release spring tension with a little lever to feed in the wires) and not the rather flaky-looking multiple wires in one hole held by a single screw. They also have the advantage that connections are either made or they are not - you can't forget to tighten the screw fully, for example.

Many years ago, as a child, I lived in an old house with very old wiring. For reasons no-one understood, there were two fuse boxes. One held the fuses in the live connections and one the fuses in the neutral connections. There was an accident waiting to happen...

 

[ignator]

Hi Lloyd,

You're lucky, here was mine:

View attachment 139995

Fortunately I had excellent but expensive insurance which covered all of my losses. \lesson? Check your insurance for cover limits - mine had no limit up to £1,500,000,

TerryD

Was root cause ever found?

 

[GreenTwin]

But on the other side of the coin, cb's do need to be exercised at some frequency, or they may fail to trip. One of the places I used to work, the 800A main breaker welded itself closed over the years. We didn't find out about it until we tried to turn it off to do an upgrade and couldn't. Had to have the utility company disconnect the transformer to de-energize. That could have been a bad day.

The main cause of failure I see in industrial switchgear is contact points that get worn, and then they overheat.
Any industrial complex that does not have an active preventative maintenance program will see fires in its switchgear.

One large company in town has a rotating maintenance system, where they completely disassemble one unit substation at a time (reduntant system, so they can take one unit sub out of service). Every single thing is checked, all bussing and wiring megger'ed, everything operated, contacts checked, and complete reports written.
The new measurements are checked against the old measurements to detect a condition that is changing.
They also energize the switchgear with the front and back open, and use an IR camera to detect hot spots.

The IR camera is probably the most useful tool that has every been created, as far as preventing switchgear burndowns.
Some insurance companies are now requiring annual IR scans on all switchgear.
IR scans allow you to detect problems that you can't see, and overheating of bussing and contacts is most of the problem with switchgear.

The other thing I see is circuit breakers used in a situation where the available fault current exceeds the interrupt capacity of the breaker.
Under these conditions, during a fault, the breaker contacts can weld shut, and prevent thet breaker from opening.
This happens frequently.

Insurance companies (for industry) are now requiring short circuit studies for the entire power distribution system, and additionally arc flash studies. This is also a good thing, and you can eliminate problems in the system, and incorrect breaker trip settings.

.

 

[GreenTwin]

Most people don't know you're only supposed to load a branch circuit to 80% capacity (either 12A on a 15 or 16A on a 20). Some kitchens have just one circuit, and we all have microwaves, toasters, crock pots, instant pots, air fryers, electric skillets, 12 cell phones, and a bunch of other stuff plugged into it. It's a miracle more kitchen don't catch fire. I guess we get lucky there.

The 80% loading is for continuous loads, but it is a good idea to adhere to this rule for all loads (I use it for all loads).

It is seldom a good idea to use an electrical device at 100% of its rating, since we know the capacity and electrical integrity of devices usually degrade over time.
There are special cases where 100% breakers are used (in industry), but you have to be careful that the entire circuit and every device/contact is also rated at 100% if you use such a device.

Kitchens in the US have had a dual circuit requirement for as long as I can remember (dating back to the late 1950's at least).
Kitchens are suppose to have "split-wired" 120 volt receptacles, ie: the tab that connects the upper and lower outlet on a duplex receptacle is removed, and separate 120 volt circuits are brought to each screw terminal on the "hot" side of the receptacle.
This does put 240 volts in these receptacle boxes, which is not a problem, since you still have only 120 volts to ground during a fault, which is no different than a 120 volt circuit.

There is much confusion about the term "hot", and I don't like to use it since it is a slang term that refers to the conductor in a 120 volt circuit that is not the neutral. The "hot" conductor must be connected to the short prong of a 120 volt receptacle, and the neutral conductor (which normally has white insulation, per Code) is connected to the longer prong/opening in a 120 volt receptacle.

Also there is much confusion between the neutral conductor and the green ground conductor.
The neutral conductor is generally near ground potential, but it does carry full current in a 120 volt circuit.
The neutral should always be insulated on its entire length, and treated just as if it where the "hot" conductor.
Current flows in a continuous loop, which is out the "hot" conductor and back to the source (typically the utility company pole-mounted or pad-mounted transformer outside your house, in the US) via the white neutral conductor.

The green ground conductor (it must be green in color per Code) is used for safety purposes, and what it does is establish a ground plane of equal (grounded) potential across all metallic items such as electrical conduits, metallic junction boxes, and the metallic frames of equipment and appiances.
The ground conductor does not have any current flow in it during normal conditions.
If the "hot" conductor happens to make contact with anything that conducts current in the system, the frame of that piece of equipment should be solidly grounded, such that the stray fault current from the "hot" conductor will immediately flow back to the upstream circuit breaker and trip it.
During a fault, there is no load impedance in the circuit, and so the fault current is high until the breaker trips on instantaneous (via a magnetic coil in the breaker).

Without a ground wire, under a fault condition, the metallic frame of a piece of equipment becomes energized, and there is no low impedance path back to the panelboard, so if a person makes contact with the metallic frame, current flows in the "hot" conductor, through the person, through the ground, and back to the panel, thus generally electrocuting the person (actually starts heart muscle fibrilation ususally).

I have seen many electrical cords with the ground prong cut off, for convenience.
This again is a "Corvair" moment, and is always extremely unsafe.
I don't use any extension cords that do not have the ground prong, and I don't use any electrical device that does not have a ground prong on the cord/plug, unless it is a device specifically designed to be "intrinsically safe" without a ground prong on its cord, due to double insulation or other means.
.

 

[Bentwings]

. There was a thing we had to do on all projects or up dates . It was called “ poke oak” it dates back to the MCarthy days of rebuilding Japan it means idiot proof. Do each project got a going over to see if saftey devices or just function was correct . Now here is what happened to me in my early engineering position. I was given the project to create new guards fo a series of 6 punch presses . There were OSHA standards first but something better was need as some “ idiot” defeated guarding and got hurt . So I came up with all new guards double operation buttons well marked saftey switches on any thing movable . Then I added switches to guard against operation if guards were removed . Then added a electrical interlock so if any switch was removed or non functional . Then added extra guardingvtomprevrn climbing over the main guards I then added infra red optical surround guarding . Then we added another circuit to deactivatvthevunitbif any wire was open circuit as redundant I then put timer switches do the trip buttons could not just be taped down Each button had to be touched in order within a time frame it was an extremely complicated thing . But the “ idiot” shut the entire electrical down by removing the wires at the central electrical box I had backup battery power too . But the guy shut the whole assembly down, then removed guards and all positive stops climbed up on top of the ram about 8 feet off the floor and tripped an electro mechanical stop , activating the press ram. He fell off and broke his shoulder. He tried to sue us but he forgot about the security cameras there were at least 4 that showed him doing his thing . He was not even qualified to operate the presses let alone service them . Some “idiots” just try to get killed. OSHA. Just tossed the suit out . He got hit with all the legal costs too.
I'm speaking as a guy who was educated at an MIT level engineering institution (Rensselaer Polyechnic), and spent 20+ years doing electronic design followed by 24 years doing mechanical design and machining. Circuit breakers are NOT as reliable as fuses. The government mandated circuit breakers because idiots were putting the wrong size fuses for the circuit, or putting pennies in the socket. (Note that they COULD'VE designed the fuse boxes to be idiot proof.) Fuses are much more reliable protection that a circuit breaker because they are a simple piece of metal that melts in response to an overload. Circuit breakers have many moving/ pivoting parts. They are convenient to reset. You don't have to go out and buy a new fuse. But that convenience leads people to keep resetting them instead of identifying the overload that caused the trip. And the more you cycle them on and off, the more wear on the mechanism. MOST of the time the wear eventually results in nuisance tripping. The breaker will trip before the specified current level is reached. But less frequently, the wear will cause the breaker to hang up and not disconnect when you have an overload. Then your house burns down. I don't know what the incidence of the failure to trip is, It may be 1 out of 500 overloads. But I HAVE seen it. So if you have a fuse box in good repair, and know how to size the fuses properly. you have better protection than a circuit breaker panel. And I would also recommend that you stop using breakers daily to turn circuits off. Incidentally, I did medical electronics design for 5 years, and learned the government does not even allow circuit breakers on medical monitors. They are protected by FUSES.

Finally, I will reinforce what others here have said about loose sockets. The increase in resistance can cause burns and fires. It is not a good idea to keep plugging and unplugging cords or heavy wall transformers.

 

[HMEL]

The shock hazard of 240v is higher than 120, the potential for arc-over wit degraded insulation and water is also greater. And 220v plugs in the UK have integral fuses, at least the ones I have.

Not true! Both systems are equally dangerous. Lower voltages tend to paralyze the muscles and as a matter of fact current of less then 75 ma will kill you if it gets across the chest and heart. Both circuits 120 60 Hz or 240 50 Hz require the same diligence when working with them. Electrical burns from either source penetrate deep into the body. Treat both with the same respect. What makes a system safe is how it is wired and maintained. The difference between the US and Uk is simply a matter of engineering design and distribution standards.

 

[GreenTwin]

I am not sure how UK houses are wired, or what sort of transformer connection feeds them, but in the US, most houses have a single-phase utility company transformer with a center-tapped secondary winding, which feeds two line conductors and a neutral conductor to each house panelboard.

Any connection line-to-line, ie: a using a 2-pole circuit breaker, creates a 240 volt circuit.
Any connection line-to-neutral, ie: using a 1-pole circuit breaker, creates a 120 volt circuit.

Most houses in the US have a single-phase connection only, generally in the 100-200 ampere range, depending on the house size.

The only way you could get a 240 volt shock in a typical home in the US is to touch the screws on either side of a 240 volt outlet.
If you touch one screw on a 240 volt outlet, you are shocked at 120 volts, same as if you touched the "hot" side screw of a 120 volt receptacle.

Most faults in electrical circuits are line-to-ground, which in a house is 120 volts.

So really, you can think of one 240 volt circuit as two 120 volt circuits, generally speaking.

The circuit to electrical dryers in the US is an oddball, which is two "hot" conductors, and one neutral conductor, plus an separate green grounding conductor.
The heating elements are connected across the two "hot" conductors at 240 volts, and the motor is connected across one of the "hot" conductors and the neutral at 120 volts.
The current across the two "hot" conductors is not equal, but that is the way it is done in the US.

.

 

[Mike Ginn]

Very interesting discussion. In the UK, residential properties have a single phase supply of 240V. The feed cable in the road is usually 3 phase and houses are connected to one of the phases as a way of balancing the load. Incidents of electrocution in the UK are rare. Electrical consumer units are fitted (or should be) with residual circuit breakers (RCDs) usually rated at 30mA which is below the danger current. Although mentioned above that 10mA is preferred, it isn't really practical due to current leakage mostly from filter circuits. Fluorescent lights are notorious for tripping RCDs. My lathe speed inverter started to trip the 30mA RCD and in the end the manufacturers removed the filter circuit. Circuits are usually wired as a loop (ring) which shares the load. Spurs are allowed and are taken directly to the consumer unit. There are regulations regarding the number the configuration of sockets in a spur. When wiring is carried out in the UK, this should be done by a certified electrician and a certificate issued. However all the components are readily available and there is nothing to stop anyone from wiring or modifying house/shop wiring. My pet hate is the connection boxed people use in their loft space. These are split female receptacles with a screw to tighten the wires. If over tightened the receptacle opens and the pressure on the wires is reduced thereby increasing resistance. This problem has long been known about but it is impossible to stop stores from selling them. My other great hate is the use of so called child safety plugs. They actually are far more dangerous than the fully shuttered sockets we have in the UK.

Its a confusing world!

Mike

 

[Lloyd-ss]

Great Discussion !
(I am the OP)
When I posted the pictures of my burned up receptacle and box at the opening of this thread, I had no idea that it would ignite (did I really say that? LOL) such a wide ranging, and sometimes impassioned, discussion. I think it has been excellent. A lot of facts, opinions, personal experiences, and personal preferences. Some of the personal preferences are in opposition to each other, and that is fine; everyone has been quite respectful about it. So now we all have to engage our critical thinking skills and figure out what works most appropriately, and safely, for us individually. Something we have been doing all our lives.

As an aside, I always check out the YouTube videos before beginning an appliance repair. But wow, what a task to filter thru them. And then after applying my critical think skills, and gut intuition, I take the approach that seems best for me. We are a bunch of pragmatic individuals who are going to do what we think is right. We are all different.

Excellent, guys !

Lloyd