Advice appreciated, No power to 2 rooms, breakers fine.

Phil-S

Joined Dec 4, 2015
140
When I read vacuum cleaner and lights in the same breath, I start to worry.
It's the sort of thing my mother did in the 50s, when power sockets were in short supply.
I don't know anything about US practice, but in the UK, lighting and power circuits are separate and each ring or radial circuit has its' own MCB (Miniature Circuit Breaker) - power is typically 32-Amps at 240-V AC and lighting is typically 6-Amps.
You could run a vacuum cleaner on a 6-Amp circuit, but it would be bad practice. Until recently, lighting circuits were not on the RCD (Residual Current Device, Earth Leakage Device) part of the consumer unit. Lighting outlets don't always have a ground terminal and the light fitting might be wired with 2-core cable.
Power circuits with the exception of heavy load items like instant shower heaters, cooker, immersion heaters, are wired as a ring circuit, so losing one outlet does not affect the others. Lighting circuits are wired as radial circuits from outlet to outlet, sio one bad outlet takes out everything upstream.
I think you need to get the whole lot checked out for wiring compliance and other hidden faults. It's particulaly important if your power comes in on overhead lines and the utility does not provide the earth/ground.
Loose cables in terminal blocks can easily overheat especially if overloaded. In my experience, even well installed wiring can suffer from screw blocks loosening up.
 

SamR

Joined Mar 19, 2019
1,819
That is why I refuse to allow "stabs" to be used for the wiring at my house. That and the fact the contact area is minuscule. Take the time to loop the wire around the mounting screw and tighten snugly. I also discovered some stab splices instead of wire nuts. Bad bad bad
 
The best practice when looping feeds from outlet to outlet is to use wire nuts and pigtails to the outlet; not using the holes in the back of the outlet. Second best is to use the screws. Same applies to ceiling lights. I had to rewire several that had been wired with crimp connections which had gone bad due to heat from the incandescent bulbs. For those, I added a junction box in the attic and ran just a single cable to each light junction box.
 

MisterBill2

Joined Jan 23, 2018
5,199
I had a failure like that in a client's residence a while back. Many outlets went dead and the refrigerator stopped running. The breaker was on and delivering power. I traced the problem to an outlet that had been installed wrong, with two wires under one screw, making a weak connection that burned open. The repair was to switch off the power and use a wire nut of a large size to properly splice the wires. Of course I did need to switch off the breaker to do that part. So probably in one of the outlet boxes, or possibly in a switch box, you will find a bad connection. The big wire nuts will cost about $0.50 each to fix the problem. AND NEVER EVER put more than one wire under a terminal screw.

There is one additional thing that can cause the same problem but it is complicated to describe the method of finding that problem. That fault mode is having a break in the part of an outlet that connects the top and bottom outlets. Poor electricians connect the supply to the top on one side and the bottom on the other and when it breaks all of the down-stream power is lost. The worst part is that you are not able to see the break in that part of the outlet.
 

MisterBill2

Joined Jan 23, 2018
5,199
That does not make sense. A short in the AC mains wiring would trip the breaker.
No power in the rooms would be caused by an open circuit.

Nevertheless, I am glad you got the problem resolved.
I once solved a similar problem that was an inadequately tightened wire nut in a junction box in an attic. One twist and the problem was solved. And an open is the opposite of a short, often more challenging to locate.
 

PhilTilson

Joined Nov 29, 2009
78
I'm intrigued that a single breaker (in the US) may well control both lights and power sockets. At the risk of stating the obvious, the breaker is there to protect the wiring. Given that (as one correspondent has noted) copper is expensive, one would expect the power circuits to be wired with a much heavier cable than the lighting circuits. The breaker must protect the power circuits and not trip unless a safe current is exceeded. However, that safe (power circuit) current may be far more than can safely be carried by the thinner lighting wiring, so protection is lost.

Or am I missing something?
 
I'm intrigued that a single breaker (in the US) may well control both lights and power sockets. At the risk of stating the obvious, the breaker is there to protect the wiring. Given that (as one correspondent has noted) copper is expensive, one would expect the power circuits to be wired with a much heavier cable than the lighting circuits. The breaker must protect the power circuits and not trip unless a safe current is exceeded. However, that safe (power circuit) current may be far more than can safely be carried by the thinner lighting wiring, so protection is lost.

Or am I missing something?
Yes, you are missing the fact that in the US, circuits in homes are only 15 or 20 Amp, 120 volt (except dryers, stoves). It is common to have the lights and some outlets on the 15 Amp circuits. I would never do that, since a short at an outlet would shut off the room lights also, but it is done here. I assume you are in the UK, where wiring is a loop of 50 Amp protected feeders and fuses or breakers at each outlet. Very different approach.
 

MisterBill2

Joined Jan 23, 2018
5,199
I'm intrigued that a single breaker (in the US) may well control both lights and power sockets. At the risk of stating the obvious, the breaker is there to protect the wiring. Given that (as one correspondent has noted) copper is expensive, one would expect the power circuits to be wired with a much heavier cable than the lighting circuits. The breaker must protect the power circuits and not trip unless a safe current is exceeded. However, that safe (power circuit) current may be far more than can safely be carried by the thinner lighting wiring, so protection is lost.

Or am I missing something?
Here in the USA mostly wiring is not divided into lighting and power. For most applications the wiring is #14 wire for 15 amp outlets and most lighting, and the higher powered feeds are #12 wire, with 20 amp protection, for locations such as kitchens and other areas that may be subject to larger loads.
For a while aluminum wire was allowed, but given the fire hazards that it created it is no longer accepted.

The reason for the mix of lighting and outlets is that it was less expensive to make fewer long runs back to the fuse box, since a feed could be shared.
 

Phil-S

Joined Dec 4, 2015
140
The US practice of wiring is nicely illustrated in this thread.
A lighting fault can take out the power sockets.
UK practice separates power and lighting circuits and others into individually protected circuits that restrict faults to particular circuits.
It's not uncommon to have 8 or more circuits in a consumer unit each with a circuit breaker. This makes it straightforward to isolate faults.
Power circuits are usually protected by RCDs, but lighting circuits are not. The logic is that power circuits with sockets is more likely to cause harm by users plugging in appliances that might be faulty - for example an electric kettle with a corroded element or a hedge trimmer that gets its' cable cut. Bear in mind, the UK and European supply is 240-V AC only, 320-V peak.
There is also an argument that losing lights to a faulty lamp creates a hazard.
For another strange reason, cookers and hot water heaters are not RCD protected. This is because they are "leaky" and prone to leakage currents to ground.
My argument is that leakage current is a fault and lighting circuits carry the same lethal voltage and current as power and should all have RCD protection. The latest regulations allow for two groups of circuits in a consumer unit to have RCD protection.
By the time a 6-Amp MCB trips, you are fried, even 30-mA at 240-V hurts.
By separating circuits, you can use appropriately sized cable and make cost savings. Lighting is 1.0 or 1.5-mm2 CSA and power 2.5-mm2 CSA (UK generally doesn't use wire gauge sizes). Personally, I would uprate both to the next size up.
Which takes me back to my mother in a 1928 built house, one power socket per room, rewirable fuses, happily ironing in the kitchen with a metal iron plugged into the two wire light pendant with a Christmas tree of adapters plus the bulb.
 

MisterBill2

Joined Jan 23, 2018
5,199
My recollection is that power at the outlets and light sockets in the UK is all either 220 volts or 250 volts, with the common side some voltage near "earth. Thus any shock will indeed be that high voltage. 110 volts or 120 will be less of a shock, still potentially lethal, but much more likely to just be a painful reminder to be more careful. As for the complaint that tripping a breaker will put the room in darkness, the reality is that usually the outlets are not all, or even mostly, in the same room as the lighting that is supplied. so mostly there is one light and several outlets. If the installations are done properly then the hazard from chaining circuits is very small, if it is done very wrong, as in the example I gave, disaster is almost certain. In that case there had been a microwave oven plugged in and the outlet was quite totally charred to bits, and inches of insulation burned off of the wires. Fortunately there was enough length remaining for a proper repair that met current standards.
In the case described in this thread it was probably NOT a short circuit, but rather an open circuit, and those are most generally caused by installers being lazy and not doing the job correctly.Outlets and switches installed with push-in wiring are an illustration of how a deviation from rules can be purchased for cash. Contrary to what some say, they are never good, although sometimes their function may be adequate. An outlet used only for charging a cell phone and an I-Pad does not need 15 amp capability.
 

MisterBill2

Joined Jan 23, 2018
5,199
Why would anyone want to go into a room without a TV? Besides, TV's provide plenty of light. ;)
The reason for choosing a room without a TV is the decision to avoid the blathering of idiots. That should be obvious! And it is very unlikely that a TV would provide enough illumination to do much that was worthwhile.
 
My recollection is that power at the outlets and light sockets in the UK is all either 220 volts or 250 volts, with the common side some voltage near "earth. Thus any shock will indeed be that high voltage. 110 volts or 120 will be less of a shock, still potentially lethal, but much more likely to just be a painful reminder to be more careful. As for the complaint that tripping a breaker will put the room in darkness, the reality is that usually the outlets are not all, or even mostly, in the same room as the lighting that is supplied. so mostly there is one light and several outlets. If the installations are done properly then the hazard from chaining circuits is very small, if it is done very wrong, as in the example I gave, disaster is almost certain. In that case there had been a microwave oven plugged in and the outlet was quite totally charred to bits, and inches of insulation burned off of the wires. Fortunately there was enough length remaining for a proper repair that met current standards.
In the case described in this thread it was probably NOT a short circuit, but rather an open circuit, and those are most generally caused by installers being lazy and not doing the job correctly.Outlets and switches installed with push-in wiring are an illustration of how a deviation from rules can be purchased for cash. Contrary to what some say, they are never good, although sometimes their function may be adequate. An outlet used only for charging a cell phone and an I-Pad does not need 15 amp capability.
The US and UK systems have exactly the same voltage to ground from each "hot" lead, so shock hazard is about the same assuming the current is from one hot side to ground, not hot to hot in the UK case. The difference is that in the US we use the center tap of the line transformer as both ground and "neutral", which carries the 120 volt current. The UK system, which really is better, does not have a neutral. All loads are 240 volts hot to hot.
 

Phil-S

Joined Dec 4, 2015
140
MisterBill2
Your recollection is correct. All power (single phase) supplied to domestic properties in UK and most of Europe is a nominal 240-V AC at 50-Hz. This is the average, but peaks at 320-V (put a capacitor on the rectified AC). This is called the Live side or conductor. The common or Neutral is roughly at ground potential, but should not be assumed. The ground used to be brought into a property by the lead sheath on the supply cable, or worse, by an earthing rod.
My property has only two conductors coming into the house, Live and Neutral. The supply company grounds the neutral at various points like sub-stations. This is called TNCS (Terre, Neutral, Combined System) or PME (Protective Multiple Earthing) and is the accepted standard. The house ground or earth is taken off the neutral at the point where the supply enters the house, usually at the company fuse and meter. RCDs are mandatory.
Such are the dangers of 240-V AC, all electrical equipment like power tools used on sites and in industry, have to be plugged into a 110/115-V isolating transformer.
The dangers of lead sheath earthing were brought home dramatically when on a building site, a plumber friend of mine was asked to remove what they thought was a lead water pipe. When the hacksaw hit the live conductor of the lead sheathed cable all hell let loose. Badly burnt and lucky to be alive, he never touches lead pipe unless it's connected to a water pipe known to supply water.
 

MisterBill2

Joined Jan 23, 2018
5,199
RIGHT! To get close to 240 off-neutral so as to get a shock, around here, one needs to work with the 480 volt three-phase power lines, which mostl have each phase about 277 volts off ground, since normally it is a wye connected transformer. But some places use a delta connection with one corner as neutral, giving a real 480 off ground. Those deliver real shocks. Fortunately none of my projects went to places that had that version of the setup.
Is there an explanation of why the UK system chose to go 240 single line instead of 120/120+neutral? It takes a bit more copper but it is much safer.
And it seems to me that there are overload protection devices at every outlet, making them much more expensive than our outlets. I usually purchase a box of ten duplex outlets for around $8, which is probably about 5 pounds or so. So there is a real price benefit to using our system.
 

Phil-S

Joined Dec 4, 2015
140
MisterBill2
Off the top of my head, I don't know why the two different systems evolved the way they did. You say center, we say centre.
I can tell you that 240-V AC is really painful, like having your arm pulled off. These days, I stick to very low voltage (24-V max) DC.
I'm so wary now, I wouldn't want to try 110-V.
The UK house wiring system hasn't really evolved much in terms of layout. Old wiring would have been all radial with just a few sockets and a few lights. The fuse box maybe had 3 or 4 rewireable fuses. There was no protection at the socket and round pins were used. The big change came with introduction of the ring circuit for sockets. Each ring, say ground floor and first floor, has its' own MCB and more recently, those MCBs would be backed up by a 30-mA RCD. Round pins went square. Australia, I believe, use the same, Europe use the Schuko plug, similar to yours
There is overload protection at each socket, but it is in the plug, not the socket. So if a local overload happens, the first go is the cartridge fuse in the plug. The actual socket costs no more than yours, but the plug is now more complex. The rewireable plug is becoming a rarity, moulded on plugs being the norm.
Lighting circuits are pretty much the same as they ever were, daisy-chained from switch or ceiling rose. As more and more lighting goes to LED only, even a 6-A MCB is overrated. I have all my lights on RCD and they have never tripped.
 

MisterBill2

Joined Jan 23, 2018
5,199
Interesting indeed. I am guessing that the device you call an "RCD" is the same as our GFI, or more correctly GFCI, Ground Fault Circuit Interrupter. My several experiences with those devices has been interesting. After spending a frustrating hour searching a clients home for a problem, I learned that they will trip even if they are wired backwards, and that when wired backwards they can not be reset, but they give the impression of being reset. I also learned that while one can still get a shock on a protected circuit, that shock is so short and weak that I did not feel them. This was while using a power tool outside in a very light rain. Some will of course scream that "nothing is more important than safety", not understanding a work ethic. Oh Well. That is not open for discussion here.
 

Phil-S

Joined Dec 4, 2015
140
MisterBill2
Yes, RCD is the same. Used to be called ELCB or RCCB (Eath Leakage Circuit Breaker, Residual Current Circuit Breaker)
Interesting that they can be wired backwards, but surely no-one does that? Useful that they still trip.
All the touches I've had on RCD protected circuits have never tripped the RCD, and they still hurt. I put that down to being thick skinned. There is a big difference between 110/115-V and 240-V when it comes to pain and danger. In case you're wondering, yes I do test them with an installation tester on a ramp test and they all pass for speed and current.
Golden rule now, always check with a meter first, and keep two bare hands off if possible. A decent pair of dry thick rubber soled shoes help as well.
Signing off, take care with Xmas lights
 

MisterBill2

Joined Jan 23, 2018
5,199
The devices that were installed incorrectly have two pairs of terminals, line in and line out. Some fool had installed it with the power sourced to the line out side. Evidently it had never been tripped after it was installed because it would not reset until I wired it correctly. What initially caused the trip was that I had used the neutral on the other side of the house as a return for a light fixture that I had added to a 3-way switched installation on a stairway. So it took a while to discover the problem. Each of the ten outlets in the basement had it's own gfci, so there was no need for any one to protect the downstream outlets.
 

Phil-S

Joined Dec 4, 2015
140
Last word on this one.
What amazes me is that domestic properties never come with circuit diagrams.
This wouldn't or shouldn't be the case in industry and more so in electronics where the circuit diagram is part of the generally, PCB build.
Even new builds don't have a set of drawings.
The real problem would be in updating information.
My property built 30-years ago didn't come with any drawings.
A few years back, tired of guessing where things went, I went round with an installation tester, starting at the consumer unit (fuse box), tracing every stretch of cable from fitting to fitting, testing each stretch and documenting it, and what a convolulted route it was.
I lifted floors where I could and installed inspection covers - digital camera very useful for looking here - every hidden junction box was brought out to the surface.
At some stage, someone knew where everything was and what was used.
If you did that in industry, where I worked, you would be crucified.
The other thing that got you in a heap of trouble was to use the draw string in a cable duct and not replace it for the next person.
I do that at home and every time I pull a cable through, usually CAT5e these days, it comes with a draw string.
Ducting for cables and services should be part of a new build, like the old steel conduit systems. What we call twin and earth has a lot to answer for - it makes installers lazy.
On the reversed GFCI, if marked at all, the ins and outs are often given slightly obscure names like source and load or L1 and L2.
But in the box or printed on the side of the equipment will be a diagram. If all else fails, the writing on the front, like ON and OFF can be a clue. If that fails, test it offline to be absolutely sure or contact the manufacturer.
 
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