Electrical Daisy-chained, parallel or series? (failed outlets in home)

[fog37]

TL;DR Summary

which connection is used for household electrical outlets

Hello Forum,

Some of my electrical outlets (3) in the kitchen stopped working (one of them is a GFCI outlet). Reading online, I found out that outlets are generally connect in a daisy-chain fashion and if one goes back they all stop working. See the figure below showing a daisy chain connection:

The connection in the figure above looks like a parallel connection (which in general assures that if a component breaks all other keep working).
But if the first device (green) in the figure break, then I believe the other two will also stop working. So this daisy chain connection is not a true parallel neither a series connection. It is more like a parallel connection but if one device breaks some of the other ones also stop functioning...

Is that correct? If so, I am trying to identify which of the three outlets is actually broken and replace it..

Thanks!

 

[berkeman]

Do the Test and Reset functions on the GFCI outlet still work, or is it refusing to reset? Do you have any GFCI breakers in your breakerbox?

Do you have an outlet tester with GFCI test capability? They are inexpensive, and very handy for debugging problems like this.

Have you ever replaced an outlet before? Do you know what-all you need to do in order to do it safely?

https://www.electricalbasics.com/electrical-testers/receptacle-outlet-gfci-tester

 

[berkeman]

Oh, and what-all was plugged into these outlets when the circuit failed? Is everything now unplugged as you try to get the circuit working again?

 

[hutchphd]

GFCI outlets typically are wired to interrupt both the attached outlet and all downstream outlets. Those further away from the box.
The ground fault is also detected universally downstream.

 

[fog37]

Hello and thanks for all the help.

• There are 3 outlets in the kitchen. One of them is GFCI. None of them works.
• I turned the specific breaker to OFF and the fridge also goes off so the fridge outlet must be part of the 3 outlet daisy chain but that works: when I turn the breaker ON, the fridge works but the 3 outlets do not.
• Cell phones were typically attached to the GFCI outlet. I replaced the GFCI outlet with a new one but nothing works.
• The GCFI has two hots wires and two white returns so it is line and load configuration.

 

[hutchphd]

How do you know there is only one circuit to the kitchen? My guess is that there may be another breaker controlling the GFCI outlet and its buddies? Possible? Its good practice to put the fridge on an isolated line.
The other handy tool for tracing circuits from a box is a plug -in radio...

 

[fog37]

dunno :)

I guess the specific switch that I turn ON/OFF at the breaker could control one, two, or more circuits.

My plan was to replace the other two outlets since I have already replaced the GFCI and things still don't work.

When I installed the new GFCI, I tried to press the test/reset but it was not working either. I am pretty sure I wired it correctly, the same way the previous GFCI was wired...

 

[hutchphd]

No I mean there may be more than one breaker (and circuit) running to the kitchen. Possible?

 

[fog37]

Yes. At the breaker, there are multiple switches for the kitchen (some are other outlets, etc.)

 

[hutchphd]

It sounds like one of them is tripped still tripped. Why do you think the fridge and GFCI are on same breaker?

 

[fog37]

It sounds like one of them is tripped still tripped. Why do you think the fridge and GFCI are on same breaker?

Because when I turn off the specific switch that I know controls the 3 outlet, the fridge turns off...

 

[hutchphd]

How do you know it controls the 3 outlet?

 

[fog37]

How do you know it controls the 3 outlet?

Because there are 3 not working outlets all located sequentially near each other, in the kitchen, by the backsplash...

 

[berkeman]

Because there are 3 not working outlets all located sequentially near each other, in the kitchen, by the backsplash...

Hutch is asking how you know that specific breaker controls those outlets. Are you familiar with how to check your breakerbox for a popped breaker? It may not look tripped visually (depends on the type of breaker). The best way is to push each breaker arm toward the ON position firmly, and see if any of them feel springy. For many of the breakers I deal with, they only move a small amount when tripped. The only way to check them is to see if they feel springy. If one does feel springy, turn it OFF and then back to ON.

Are there any other outlets in the house that are not working? At least in the US, as far as I know it would be a code violation to use the refrigerator circuit to also power other outlets -- by code it is supposed to be a dedicated circuit, AFAIK...

 

[fog37]

I am confident I pushed the breaker arm towards OFF and towards ON firmly. Will try again. When on OFF, also the refrigerator turns off hence its outlet is connected to the other 3 outlets that are not working...

 

[berkeman]

No, my point was to check all of the *other* breakers in the panel.

If the outlets kept "not working" when you turned the fridge breaker OFF and ON, that does not mean they are on the same circuit...

 

[fog37]

Ok. I see. Wil try and report back. Thanks!

 

[fog37]

No, my point was to check all of the *other* breakers in the panel.

If the outlets kept "not working" when you turned the fridge breaker OFF and ON, that does not mean they are on the same circuit...

Hello, I tried all other breaks and no luck. Also, now I remember, the outlets stopped working for 5-6 hrs. Then worked again. No don't work at all...Something loose? Would replace the other two outlets possibly solve it? One of them may be damaged. I already replaced the GFCI one but no luck...

 

[berkeman]

I wouldn't replace other outlets right now. It does sound like a wire connection came loose somewhere.

What room is in the other side of the wall with the dead outlets? Living room, bathroom, etc.? Do the outlets on the other side of that wall all work?

Do you have access to the attic? What kind of house/apartment is this? Multi-story or one story?

If you have access to the attic, you may be able to trace the power cables from the breaker box (in the garage?) to the top of the kitchen wall. If you can do that, you can check the the junction box at the top of the wall to see if it looks like all the wire nut connections are okay.

 

[berkeman]

One of them may be damaged.

I missed this. What do you mean by "damaged"?

 

[berkeman]

[Mentor Note -- Moved the thread from EE to the DIY forum]

 

[fog37]

I missed this. What do you mean by "damaged"?

Just using "damaged" loosely for "not working". Why wouldn't a loose connection be a possibility given that they did not work, then work, then stop working again?

 

[hutchphd]

Did the other GFCI ever indicate with a light a ground fault?
So you are certain the wire goes... breaker box-----fridge------GFCI----outlet-----outlet?
If so the problem is somewhere in red and you may now have a spare GFCI. Start at the easiest spot to open and start checking the wires in red for volts. Probably at a connection.

 

[DaveE]

The other handy tool for tracing circuits from a box is a plug -in radio.

OK, I've been a bona-fide Analog & PS EE for 40 years. I completely rewired my kitchen and garage without any complaints from the building inspectors. But, I never knew this trick. I always used lamps, then I had to walk back and forth to see if they were on or not. Thanks, you simultaneously saved me a bunch of work someday in the future and made me feel like an idiot!

 

[hutchphd]

I saw it on TV about 30 yrs ago. I had exactly the same DOH! response. I never forget a labor saving tip.

 

[DaveE]

OK, my apologies if I have misunderstood. But... If you don't know all about how normal GFCI outlets are wired, via web searches or DIY books, then you shouldn't be messing with this. I don't think the wiring is at all difficult to understand. By skipping the research and education part of this project you are taking unnecessary risk. Honestly the basic concepts are easy to apply, and we may misunderstand your question and give bad advice or think we know more than we do. Some things are easy to understand and HAVE TO be done correctly.

OTOH, I haven't seen bad advice in this thread (yet).

 

[fog37]

Did the other GFCI ever indicate with a light a ground fault?
So you are certain the wire goes... breaker box-----fridge------GFCI----outlet-----outlet?
If so the problem is somewhere in red and you may now have a spare GFCI. Start at the easiest spot to open and start checking the wires in red for volts. Probably at a connection.

That is what I thought: a faulty GFCI. But when I replaced it with a new one the problem remained. I will get a voltmeter and check the volts...

 

[hutchphd]

Could be the connection at the fridge outlet too. No other junctions, probably. But I lived in one house where I found aluminum wires twisted onto copper wires inside the wall cavity with no box. So you never know.

 

[fog37]

Could be the connection at the fridge outlet too. No other junctions, probably. But I lived in one house where I found aluminum wires twisted onto copper wires inside the wall cavity with no box. So you never know.

Could be. Need to move the fridge. Hard for me to know the exact wiring. It came with the house so I am not sure. I see how GFCI work: it senses small difference between the current in (hot wire) and the current out (white wire). If there is a difference, the GFCI interrupts the circuit.

That is why it would makes sense that the problem was the GFCI outlet. Unless the refrigerator is also connected to a GFCI (need to move the fridge) and that is faulty...But how would the refrigerator work while the other daisy chained outlet don't?

 

[berkeman]

Unless the refrigerator is also connected to a GFCI (need to move the fridge) and that is faulty

No, unless the electrician who wired the house was a complete idiot and did not have the installation inspected for code approvals, that would not be possible.

 

[hutchphd]

Check the easy stuff first (voltage into GFCI) . And I wouldn't put the fridge downstream of GFCI because I like ice cream. But the line (both hot and neutral) from fridge outlet to the GFCI is primary culprit in my mind including all connections.

 

[fog37]

Check the easy stuff first (voltage into GFCI) . And I wouldn't put the fridge downstream of GFCI because I like ice cream. But the line (both hot and neutral) from fridge outlet to the GFCI is primary culprit in my mind including all connections.

Same here about ice-cream :) But if the line is the culprit, then I guess I need to call an electrician. I wouldn't know how to repair a broken line that is inside the wall. So far I can only replace outlets...

 

[Klystron]

I saw it on TV about 30 yrs ago. I had exactly the same DOH! response. I never forget a labor saving tip.

I must have RF on my mind.

Until DaveE clarified the method; after skimming the posts, I thought hutch meant to use radio frequencies to troubleshoot ac circuit 'damage'. IDK, perhaps TDR (time-domain reflectometry) for home wiring? Set up rf tx/rx to detect ac circuits...? I--D--K

I also use electric lights for basic testing. Used to carry a simple 'light up' detector in my pocket to test before touching something 'hot'. My earliest EE mentor was deaf in one ear and hard of hearing in the other -- I had to explain stereo sound to him -- and professionally, I often worked in high noise environments. So, never thought of using a radio. Also, I like reflecting the light off surfaces such as ceilings to detect changes at a distance. Still, what a great idea.

Imagine "Inna Gadda da Vida" blasting at max decibels for testing AC circuits; "Ding-Dong the Witch is Dead" sung by munchkins with Alvin and the chipmunks as backup band, for DC.

 

[berkeman]

Until DaveE clarified the method; after skimming the posts, I thought hutch meant to use radio frequencies to troubleshoot ac circuit 'damage'. IDK, perhaps TDR (time-domain reflectometry) for home wiring? Set up rf tx/rx to detect ac circuits...? I--D--K

LOL, that's too funny.

Although you are right, you could use a TDR/cable tester to figure out how far from the breaker panel the wiring problem was. You'd still need to crawl through the attic to measure the cables and find it though.

 

[DaveE]

Hard for me to know the exact wiring. It came with the house so I am not sure.

That's always the hardest part of these jobs. You know and expect the "normal configuration", but that's not always what the guy before you thought "normal" was.

 

[berkeman]

That's always the hardest part of these jobs. You know and expect the "normal configuration", but that's not always what the guy before you thought "normal" was.

Definitely, which is why the inexpensive outlet tester that I mentioned is important to get and use on all of our outlets...

Do you have an outlet tester with GFCI test capability? They are inexpensive, and very handy for debugging problems like this.
https://www.electricalbasics.com/electrical-testers/receptacle-outlet-gfci-tester
View attachment 276311

 

[fog37]

I have been thinking: the GFCI outlet has two hot connections (top hot is for the hot line, bottom is hot load) and two neutral connections (top is return line, bottom is return load). I connected the black wires and white wires the way they were connected on the GFCI that I replaced...

However, is it possible that the new GFCI outlet is not working because of line-load reversal: the black line hot wire may be connected to the GFCI hot load connection instead of to the GFCI line hot connection?
Same for the load lines: maybe the load return is connected to the the GFCI line return connection and the line return is connected to the GFCI load return...

Is the line cable always on the left and the load cable always on the right on the inside of the receptacle like in the figure below? MY receptacle looks like that with a cable on lower left and a cable on the lower right...

How can I verify that line-load reversal is not happening using a voltmeter? I guess I can check the voltage between the hot and neutral for each cable with the breaker on and no GFCI outlet connected to identify the load and line cables...

 

[hutchphd]

It is typically marked on the GFCI. With the breaker on, do you get 120 VAC across one cable wire (black to white)? Then put those in the "toward box" (or whatever it says) connection and you should be good to go.

 

[fog37]

It is typically marked on the GFCI. With the breaker on, do you get 120 VAC across one cable wire (black to white)? Then put those in the "toward box" (or whatever it says) connection and you should be good to go.

Thanks!

Yes, the back of GFCI has line connections (lugs) on top and load on bottom. Will get voltmeter tomorrow to make the measurement between hot line and return line. If I get 120VAC, that is the line.

The GFCI outlet currently has a permanent small yellow light turned On and pressing set/reset button does nothing and does not engage...

 

[fog37]

Update. Problem solved :)

I got a non contact voltage tester and identified the live hot wire from the hot load wire. I realized I did a line-load reversal. So all works just fine now.

Thanks for the discussion. It surely forced me to think about the problem and all its facets more deeply.

In regards to the non contact AC tester, I thought it was quite a nifty tool since it can detect voltage from just one wire by using capacitive coupling since the voltage is AC.
First I thought "How is it possible since voltage is always between two wire" but then realized that the other "wire" is, at least I think, the tester and me with my body connected in some fashion to the ground...Is that correct? The change $\Delta V$ is the potential difference between the potential $V_2$ of the live hot wire and the potential $V_1$ of tester+me both poorly connected to the ground...Does that make sense?

 

[berkeman]

Glad that you are back up and running.

Do you still think that the same breaker controls the refridgerator and those outlets? At some point (home remodeling, inspection before the sale of the house, etc.), you may need to have that fixed:

https://www.thespruce.com/kitchen-wiring-circuits-1152911

EDIT/ADD -- Now I'm seeing some indications that it may not be an NEC requirement, maybe just a regional requirement. You can call your local city inspection department to ask.

 

[hutchphd]

Thanks for the discussion. It surely forced me to think about the problem and all its facets more deeply.

Yay

Your analysis of the voltage "sniffer" is pretty good. The key is I believe capacitive coupling between the hot wire and the tip of the wand. One the other side effectively is you (a large capacitor). So AC voltage is induced in the wand and a FET let's us see it.

 

[fog37]

Glad that you are back up and running.

Do you still think that the same breaker controls the refridgerator and those outlets? At some point (home remodeling, inspection before the sale of the house, etc.), you may need to have that fixed:

https://www.thespruce.com/kitchen-wiring-circuits-1152911

View attachment 276367

EDIT/ADD -- Now I'm seeing some indications that it may not be an NEC requirement, maybe just a regional requirement. You can call your local city inspection department to ask.

My understanding is yes: the same breaker controls the refrigerator (upstream of the GFCI) and the GFCI which controls the other two regular outlets. With the GFCI out, the refrigerator kept working but GFCI and the other two outlets didn't.

Thanks

 

[sophiecentaur]

Summary:: which connection is used for household electrical outlets
I am trying to identify which of the three outlets is actually broken

So this daisy chain connection is not a true parallel neither a series connection.

Incorrect. It IS a true parallel connection. Any current through one connected appliance will never pass through another. Don't ever be misled by the route that the actual cables take (easy done). It's the connections that count. All the L cables are at the same potential and all the N cables are at the same potential; that is termed Parallel.

The caveat, stated in some previous posts, applies. If you are not familiar with all of the following then you should really get paid help. (Your series / parallel confusion makes me uneasy.) Fault finding often involves a lot of things in one session and it can be hard to do it through Q and A on a forum. Experienced Electricians tend to do it 'all at once', without needing to think. Solving some problems may take a lot of time. for those with not much experience.

I am late to this thread so I may be repeating the following - in which case, apologies. There is almost certainly no need to examine the buried cables but it's perfectly possible to examine each outlet and the wire connections. You need to isolate everything first - best to turn off at the mains input to the distribution box, perhaps.

Is your GFCI on one outlet or at the breaker box? Or are there two? An outlet GFCI (certainly a replacement one) will not affect other circuits or even other outlets on the same circuit. Your information, so far, is a bit confusing. Is the GFGCI a 'plug in' or is it inside a wired outlet?

Remember that a GFCI can trip even if there is a small current to Earth via the Neutral side. So you need o disconnect both legs of the circuit it feeds. It sounds to me that you could have a Neutral - Earth short somewhere along the neutral side of the circuit. Just to disconnect the live side will not sort that out.
If the apparently faulty outlet is the culprit then (a photo first, if you're not confident) First disconnect the downstream cables. What effect does that have on the situation? The leak could have existed for a long time but may have increased slightly without human intervention.

Disconnect the input cables to the faulty outlet and examine them in detail. With the downstream circuit isolated, a Meter will show any continuity (it doesn't need a total short) between LN,NE and NE wires.

GFCI outlets typically are wired to interrupt both the attached outlet and all downstream outlets.

That sounds very unlikely - although I can't speak for US installations. An outlet with GFCI it there to protect the user of appliances plugged into that outlet alone. Any other arrangement could be very inconvenient. How would you know which other important appliance could be affected if your garden tool chops through its cable? But at the name "Outlet" tells you its purpose. How would the cables at the back be connected? You'd need an extra pair of terminals with a specific IN and OUT function.

A GFCI in the breaker box will, of course switch off the whole of that circuit and it doesn't have an outlet connector at the front.

 

[hutchphd]

That sounds very unlikely - although I can't speak for US installations

It may sound unlikely to you (I don't know why) but it is most certainly true in the US. The outlet box interrupts both sides of downstream connections (including the socket itself). Knowing this fact has allowed me to heroically aid many do-it-yourselfing friends.

 

[sophiecentaur]

It may sound unlikely to you (I don't know why) but it is most certainly true in the US. The outlet box interrupts both sides of downstream connections (including the socket itself). Knowing this fact has allowed me to heroically aid many do-it-yourselfing friends.

Over the years I have come across many differences between US and UK wiring practices. This is one that strikes me as 'inconvenient' (other words come to mind lol). Using that system means that, unless you know the details of your wiring circuit, you won't know whether or not an appliance on that circuit is protected. That strikes me as a serious drop-off. You would need to know whether it is upstream or downstream of the GFCI and that would involve actually activating the breaker and then checking on all (unknown) appliances. In UK, of course, the RingMain system is used so there is no daisy chaining of outlets and there are two paths to any outlet. Any socket on the ring is either protected or not, according to what sort of sub-breaker' is used. But it's a different world and you have to view systems as a whole. If that system is accepted then fair enough but what actually is the advantage of it?

PS While we are on the subject of US mains connectors, why do the pins all seem to have a hole drilled in them, near the end??

 

[hutchphd]

I don't know about the "why holes?" except that occasionally I do some very ad hoc temporary test wiring by putting 18 gauge stranded through them and twisting it on. Also probes and test clips.
All GFCI I know have a test button so you can trigger them and thereby see which things get shut off. It is also quite nice for instance in my garage the first thing I wired incoming is a GFCI outlet and everything else is then automatically protected including lights and switches. In the bath it also means the wall sconce lights can usually be protected easily without a dedicated GFCI breaker in the box.

 

[sophiecentaur]

I do some very ad hoc temporary test wiring by putting 18 gauge stranded through them and twisting it on.

Wow. Sounds like the Wild West. In very nearly every respect (except for the initial choice of Voltage), the UK electrical philosophy seems more fussy about safety issues. The UK Ring Main system is as much a mystery to US and the 'split phase' US system is likewise a mystery to the UK.
The sayings about US and UK being divided by a common language also apply to Electrical matters, I think. It's taken me a long period of exposure to the US point of view to realize that it's really not all that bad. But, if I ever spent time as owner of a US property, I know I'd spend a long while going tut tut and shaking my head when I looked at the domestic electrical situation. And I'd bet the reverse would apply to you.

 

[hutchphd]

, I know I'd spend a long while going tut tut and shaking my head when I looked at the domestic electrical situation. And I'd bet the reverse would apply to you.

Let me assure you the wiring kludges I mentioned are strictly momentary test setups. I did mention above finding aluminum and copper wire twisted into a splice in the open in a wall cavity. No arcing after 30 yrs thank god.
Also 120 volts is much more forgiving than 220 (probably 4 times more forgiving!) It can kill you but you need to be very stupid. My only truly potentially disastrous electrical experiment was me at age 13 with my trusty Van de Graaf and a home-made leyden jar. Lots of energy there. I put it away.

 

[sophiecentaur]

probably 4 times more forgiving!

This is true but electrocution is still extremely rare. This is partly because people are actually 'scared of 240V electricity' (in the same way that they are scared of circular saws), I think. The regulations for using electrical appliances under risky conditions (building sites etc.) require the use of 120V and isolating transformers (and nowadays you find GGCIs everywhere.)

I am more than happy with the available equipment and regs for domestic electrical supply here. Those 'over-sized' 13A fused plugs are not always handy but the RingMain system means that you usually find a lot of outlets in any room so that extra dodgy 'adaptors' are not often needed. EU is also fussy about these things. I guess that my experience of US Electric Supplies is strongly coloured by the posts that you can read on PF, from Off-Grid enthusiasts and the like. Those guys are much less common in UK because (alas) we don't have the open spaces for them but their stories can be read here.