# Voltage Problem - Lighting Circuit



## middle.road (Nov 6, 2015)

OK, I've got a strange one this morning. I was up in the shop attic putting some stuff away,
came back down, sipping some coffee, and one of the two (4) lamp fixtures on the ceiling went out/off.
There are two of these in the ceiling controlled by a switch over at the door.
The far one is fine, the near one is out. I removed the fixture and tested the voltage at the line.
84v is all?!? Why would it be 84v? I've attached a basic schematic and a pict.
Circuit is on a 15A breaker, and controls these two, plus (3) flouresents on a switch, and the outside LED,
all joined up at a junction box above the circuit breaker panel.
I KNEW I should have re-wire the garage when we were moving in and it was empty. This place has
been a nightmare in regards to wiring. I'll have to clear out a bunch of crap to take up the OSB I laid
down two years ago. *SIGH*
Thanks in advance as always.


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## ch2co (Nov 6, 2015)

If this is truly the total electrical path between the lights, the only thing I can come up with is the there is a large resistance in the wiring between the two lights.
This means that a large amount of heat could be generated in the wiring either at or between the two lights.  T


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## middle.road (Nov 6, 2015)

It's a best guess of what I remember before I laid down the OSB. 
I'm going to go up in a bit and start excavating. Heart and mind are willing to do the ladder, the knees however...


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## ch2co (Nov 6, 2015)

SORRY MUST HAVE HIT THE WRONG KEY OR SOMETHING

This could be dangerous and a fire hazard!  

I would look at the connections at each lighting fixture and assure that the wiring is secure at the connections.  See if anything is hotter than it should be.
The next thing could be an almost broken wire in the system as the source of the problem.  If you aren't familiar with wiring and handling this sort of thing,
Turn off the lights!  Keep them off. Call an electrician.  

Chuck the grumpy old guy


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## middle.road (Nov 6, 2015)

I killed the circuit when I read 84v on the meter.
Just went out to set up trouble/Aux lighting so I can see properly, and get this: One of the clamp lights I bought at the electrician's estate sale a week 
ago shorted and popped the breaker. Figures - doesn't it. Just cut the cord off that puppy...
Treading very carefully from here on out. I think the gremlins have overridden the shop/garage.
I'm going to go out and test everything with a voltage tester shortly just to be certain.
(perhaps an all rubber suit with gloves and boots is in order... )


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## CluelessNewB (Nov 6, 2015)

Most likely a bad connection at one of the lights.  With the breaker off check that all the wires are securely twisted together and have a wire nut of the correct size.   I suspect you will find one wire that slipped out of the wire nut and probably wasn't securely twisted together when it was installed.


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## middle.road (Nov 6, 2015)

Well when I stashed the unused shopvacs up in the attic I managed to set them on top of the wiring running over to the second light.
(Creeping Elegance™) And there are insulation batts throughout. A small shopvac resting on insulation, and.... Gimme a break.
And then there is the totally incorrect and messed up wiring running to the fixture.


--- Tape Removed (Ugh!) insulation slice on both...



--- Then at the 2nd Fixture. I don't even want to see what's under this tape. Taking a break from it for now to calm down.
This wiring is this house is unbelievable. Who in their right minds looks at that and says, 'That's Good.' ?
You don't splice outside a junction box! *GADS*


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## TOOLMASTER (Nov 6, 2015)

should be like this


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## Silverbullet (Nov 6, 2015)

You may have just saved your shop and more. I'd be looking at all the wireing in the place .Plus the wires should be stapled to the beams not just free floating.


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## Bill C. (Nov 6, 2015)

Consider replacing the wiring with either steel conduit or armored cable and outlet boxes.  Glad you notice it before the building caught fire.


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## Hawkeye (Nov 7, 2015)

If you're not comfortable (i.e. experienced) with electrical work, consider hiring an electrician. I see 'work' like that all the time, done by someone who thought he was capable. Your peace of mind is worth something.


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## mksj (Nov 7, 2015)

Terrible wiring, voltage drop not tripping the breaker is probably an indication of a poor wire connection increasing the resistance  as others have indicated.  A few notes; Typical current carrying wires "Hot" side for residential AC wiring is always black or red (usually 2nd leg in single phase 240VAC or switched leg in a 3 way switch) insulated wire. White wire is always neutral (unless marked with electrical/colored tape at each end), which is bonded to earth at the main panel only. Green or bare copper wire is always ground. Romex is fine in an enclosed wall or ceiling, I do not see any need/cost for shielded cable if local electrical code does not require it. Romex needs to be secured with manufacturer approved staples (I prefer the plastic ones) at least ever 4 1/2 feet or less, 12" within a box or receptacle when secured, or 8" if not secured at the entry point into the box. An accessible box is needed for any junction.


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## John Hasler (Nov 7, 2015)

mksj said:


> voltage drop not tripping the breaker is probably an indication of a poor wire connection increasing the resistance as others have indicated.


There is no way for the breaker to know that part of the voltage drop is across a bad connection and not all across the load.  Breakers detect excess current.  Bad connections result in reduced current (and heat in the bad connection).  An arc fault interrupter *might* have detected this, if the bad connection was arcing.


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## jim18655 (Nov 7, 2015)

Like Jon said, you might want to replace the lighting breaker with an AFCI. It might save your building in the short term. You might need the AFCI for the rewire work anyway depending on the local building codes.


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## middle.road (Nov 7, 2015)

Thanks Toolmaster for the diagram. That is how it was. I revised the one in the first post.
And the verdict is (possibly) Bad connection at wire nut. The neutral leg running over to the 2nd fixture was loose. (Red Arrow)
Must have hit the box just right with the shopvac to knock it loose. The three wires were just placed together in the nut and it did not take
any twisting at all to remove the nut. On the two 'HOT' wire nut connections, the wire were _somewhat _twisted together.
The neutral wire at the first fixture was also hosed. (Blue Arrow)
Re-did everything, ran a new hunk of romex over to #2.
Garage was framed out of rough cut 2X's, and man they get hard as they age. Makes putting staples in very difficult.


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## middle.road (Nov 7, 2015)

And electrical question. I mounted the fixture and turned on the power. When I take the non-contact detector/indicator and get close to the
body of the fixture (~1") it starts beeping like it's hot. This is all around it. Bad fixture or just so many hot leads inside it?
At that point last night I threw the breaker and packed it in for the night.

Thanks gang for all the replies and help!


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## jim18655 (Nov 7, 2015)

Probably too many wires. Some of those testers only need about 50 volts to trigger but they shouldn't show anything on a ground or grounded conductor. They will show power on an open neutral. If in doubt check with a real meter from the fixture to a known ground away from the light. The lamps will also trigger a response.


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## mksj (Nov 7, 2015)

John Hasler said:


> There is no way for the breaker to know that part of the voltage drop is across a bad connection and not all across the load. Breakers detect excess current. Bad connections result in reduced current (and heat in the bad connection). An arc fault interrupter *might* have detected this, if the bad connection was arcing



That is what I stated. My point is either it shorts and trips the breaker, or there is a bad connection which could heat up and could cause a fire. An Arc fault would most likely not detect this if there is a measured voltage drop, unless the connection heats up to the point of melting/burning the contact which could lead to arcing. AC lines can also generate phantom (ghost) voltages in wires running together, you often need a LoZ voltmeter/multimeter  (low impedance) to measure AC voltages correctly. "Ghost voltages occur from having energized circuits and non-energized wiring located in close proximity to each other, such as in the same conduit or raceway. This condition forms a capacitor and allows capacitive coupling between the energized wiring and the adjacent unused wiring."


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## TOOLMASTER (Nov 7, 2015)

+ since you are using fluorescent bulbs that have coils anything is possible...throw them away and get leds....they are nice and bright.use even less power... i just did the whole house...always hated the fluoro's...had 3 catch fire


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## TOOLMASTER (Nov 7, 2015)

i am wondering if you have a bad ground on the whole system....put on some rubber gloves and check the wire from main box  to water pipe or ground rod....if you have a bad ground the power that goes through anything livens up the whole ground circuit....


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## ch2co (Nov 7, 2015)

[QUOTE=When I take the non-contact detector/indicator and get close to the body of the fixture (~1") it starts beeping like it's hot.

I have one of those detectors and they're useful for what they do, see if a circuit is on or off.  When I take mine and wave it anywhere near my computer when its plugged in, it beeps within about 2 to 3" away.  Likewise for my desk lamp, television, and most things even if they don't have a metal exterior. If I go into my shop, where everything is three wire  i.e. grounded, there isn't a peep unless I insert it into the hot side of an electrical outlet.I just tried it on the plastic exterior of an LED ceiling light in my office and even in my shop where the boxes are grounded and it beeps. Don't rely on these non-contact devices to check electrical circuits for anything but on or off at the electrical outlet, thats all that they should do. To trust them for a grounding problem could prove shocking or even fatal!  Use contact type devices, i.e. digital multimeters, that are designed for this purpose, and always wear proper gloves (and safety glasses). If you don't know what y0u are doing, don't do it, get an electrician.

Chuck the grumpy old guy


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## tomw (Nov 7, 2015)

middle.road said:


> View attachment 113881



I'm sure you know this, but that is way to many wires in a box of that volume. If you can, upgrade the box to a larger volume.


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## middle.road (Nov 8, 2015)

Didn't even get to set foot in the shop yesterday. Going to check and verify the ground when I get out there today.
Which reminds me - I bought a copper grounding rod when I redid the circuit for the garage to 6GA. It's resting
against the backside of the garage. I forgot all about installing it... That was September I think. 

I use the detector religiously whenever I do anything in this house. It has saved my arse several times now.
It stupidifies me the way that the POs ran wires and made 'splices', actually it's downright scary.
Live wires running in places that defy logical sense.  

The wire in the box is cleaned up a great deal. Not so congested now. 

I plan on switching to LED's as soon as our stock of CCFL's is depleted. We had one of those Energy Audits done 
last year and the guy left us a dozen bulbs as part of the program.
What I'd really like to do is replace both fixtures with LED and brighten up the dark area of the shop.

Looking at GFCI breakers this morning, going to get one through EBay, they're $50 at the BigBlueBox.


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## jim18655 (Nov 8, 2015)

You want Arc-fault (AFCI) not ground fault (GFCI).


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## Bill C. (Nov 8, 2015)

I think ground rods are overlooked sometimes.  They just sit there buried ten or more feet underground.  Depending on the soil moisture to conduct the energy away. If yours is like mine the electric, phone and cable use the same rod.


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## Brnoczech (Nov 8, 2015)

Amazing what you find.  20 years or so ago I had a second story room added over our existing garage.  This was done by  a company that built custom homes.  Obviously it involved electrical work.  When I put my shop in about 10 years ago I hired an electrician to run electric from the breaker box through my attic to a new box he installed in my garage.  When he was in the attic he noticed a wire (Romex I think) that was part of the original wiring in the house, and which ended about head high on a rafter.  I looked at it and assumed it had been killed.  It was simply cut off and wound around the rafter; no box, tape or anything.  He tested it and it was live.  I immediately thought of all the times I had been in the attic over that ten year period with my head/hands only a few inches away.  Pretty scary.


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## John Hasler (Nov 8, 2015)

Bill C. said:


> If yours is like mine the electric, phone and cable use the same rod.


That's desireable.  It will reduce the risk of lightning damage to your phone and electronics.  The phone companies usually want to set their own rod, though.

BTW if you have a well tie the well casing into your grounding system.


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## middle.road (Nov 8, 2015)

Brnoczech said:


> Amazing what you find.  ...  It was simply cut off and wound around the rafter; no box, tape or anything.  He tested it and it was live.


My first house here in TN back in 2000, had an unfinished basement, they had started it sometime in the past but all that was completed at that point
were wall studs. It was only a few years old when I bought it.
Along a back wall were (4) rolled runs of Romex hung on the wall, all live, all untaped or nutted even. It is amazing how some Romex run are laid down.
This current house is full of taped splices. It's like "oh, I need a circuit over there, I'll just splice into this line here..."
As soon as I come across one of those, I kill the circuit - break out my electrical tote, grab the Romex and replace it.
It's a small place, (2) bedroom. The living room and master bedroom were remodeled in 2001. The outlets looks good, 3-wire romex, properly installed.
but none had a ground. They were wired, but what they did was ran the Romex up the wall and at about six foot, spliced it with the original 2-wire that
ran back to the main panel. Took me two days to figure that one out.




John Hasler said:


> ...
> BTW if you have a well tie the well casing into your grounding system.


Hmmmm... The well is about 30' from the house Main Panel, and about 40' from the Garage Sub Panel. I'm going to check that out.

And I still have not made it into my shop this weekend...

Thank you again gang for all the ideas and info. I enjoy this forum and how it is friendly, congenial, and has great replies/answers to boot.


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## middle.road (Nov 8, 2015)

It was the ground! One down, one to go.
Two days wasted dinking with lousy wiring when I could have been cranking handles perhaps...


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## mksj (Nov 9, 2015)

Please note that NEC electrical code [210.8(A)] specifies GFCI for garage, basement, crawl space, etc. Arc fault is usually specific interior spaces and also may vary with local code. Arc faults AFCI do not play nice with machinery that sparks, some power tools with motors (saws, grinders, shop vacs, etc) may trip an AFCI. There are also DFCI breakers that combine both, that are now mandated for kitchen and laundry areas. GFCI's often will trip with VFD machines.


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## middle.road (Nov 9, 2015)

What I'm thinking is, since I can't see the wire running down the wall to the switches, and since this circuit has only lights on it, 
put a AFCI in the panel to cover that unknown. Actually I just don't wan't to tear apart the wall - and remove all the shelves and such.
These two (4) bulb fixtures, (4) Fluorescent twin-tubes, and the LED outside.


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## aliva (Nov 9, 2015)

Check all your neutrals, if one or more are loose, the ground ends up becoming the neutral and you'll see a low voltage. This happened to me about 2 months ago installing a new receptacle


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## John Hasler (Nov 9, 2015)

aliva said:


> Check all your neutrals, if one or more are loose, the ground ends up becoming the neutral...


This can only happen if you have a neutral to ground fault somewhere.  If any current flows with the neutral interrupted something is very wrong.  A loose neutral in the box can cause low line to neutral voltage at the load, though.


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## middle.road (Nov 9, 2015)

Let there be light!


And now I need an education or lesson in electricity.
Before I screwed everything back together I tested the fixture without the ground attached.
Gloves on, power on, no bulbs, I connected the Fluke to the ground inside the box and contacted the outside of the bulb housing
and it was reading 4.8VAC and the detector was squealing. Nothing on the Neutral to Ground.
Connected the ground and all's good. I guess I just don't understand the basics of AC power.
I checked out both fixtures on the bench before I wired them back up, checking to see if any of the sockets or the switches were
shorted to the metal case. They were all good. I am so confused. Too many wires in the socket portion of the fixture?

Thanks.


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## tomw (Nov 9, 2015)

The neutral and ground are connected at the main panel, so seeing continuity is OK. However, you should see zero voltage potential. Have you checked for potential between the neutral and ground with the fixture removed from the circuit (obviously cap the hot and move carefully)? If that is zero, stop and throw away the fixture. If not zero,  then check at the panel between the neutral and ground. If that shows potential, something is really wrong.


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## John Hasler (Nov 9, 2015)

middle.road said:


> Let there be light!
> View attachment 114057
> 
> And now I need an education or lesson in electricity.
> ...


There's nothing wrong.  There is a tiny amount of capacitance between the hot wire inside the fixture and housing.   The Fluke has an impedence of 10 Megohms so the fraction of a microamp of current that flows through this capacitance shows up on the Fluke as a few volts.


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## CluelessNewB (Nov 9, 2015)

John Hasler said:


> There's nothing wrong.  There is a tiny amount of capacitance between the hot wire inside the fixture and housing.   The Fluke has an impedence of 10 Megohms so the fraction of a microamp of current that flows through this capacitance shows up on the Fluke as a few volts.



Love my Fluke digital but sometimes the old analog Simpson 260 just works better


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## middle.road (Nov 10, 2015)

CluelessNewB said:


> Love my Fluke digital but sometimes the old analog Simpson 260 just works better


I've got a couple of 260's sitting in a drawer, I would say it is time to dust one off and change the batteries. 

Time to get off my arse and install the grounding rods. I've been pondering a run to the old well casing, but there's the distance and two sidewalks to contend with.
I've got the house main panel and the sub panel in the garage to do.


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## tomw (Nov 10, 2015)

Crap, I read that as 48V. Yes, 4.8V will be from induction or capacitance. Which one is academic. I am sorry for not reading more carefully. 

If it was 48V, then my comment is still probably an OK approach.

Mea culpa,

Tom


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## middle.road (Nov 10, 2015)

tomw said:


> Crap, I read that as 48V. Yes, 4.8V will be from induction or capacitance. Which one is academic. I am sorry for not reading more carefully.
> 
> If it was 48V, then my comment is still probably an OK approach.
> 
> ...


Fault? whose fault? Those decimal points get trickier with age - I hear. All good. I was hoping it was a force field of some sort.
Didn't feel like going out and finding new fixtures. Would like to go LED as soon as the budget allows.

In other news - I revived one of my simpsons... Forgot how many batteries those puppies take.


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## TOOLMASTER (Nov 10, 2015)

EMF is everywhere power is..  old 2 prong water bed heaters would light up the water and you..


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## middle.road (Nov 11, 2015)

TOOLMASTER said:


> EMF is everywhere power is..  old 2 prong water bed heaters would light up the water and you..


And the smell of burnt vinyl and the mess...


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## Wireaddict (Nov 15, 2015)

I've also seen this problem caused by loose neutral neutral connections at the transformers, meter sockets & in panels.  Ultimately all neutral wires [& grounds] need to end up connected to the center tap in the secondary of the power company's transformer.  Loose connections between the panel neutral bus & the tranny center tap cause the panel neutral potential to "float" instead of being about zero volts with respect to ground & about 120 volts with respect to either [240 volt] hot terminal.  That wasn't your problem but if lights dim or brighten a lot when 120-volt motors or heaters start check voltage between neutral bus & power line in terminals on either side of your main breaker with these devices are on.  I've seen several main breakers develop resistance with age [mainly 100A breakers].  [A weird & rare occurrence that can happen is that a neutral connection opens up in a building & the neutral unbalance fault current flows between ground ground rods &/or cold water pipe bonding to those in neighboring buildings, particularly if they're fed by the same tranny.]


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## uncle harry (Nov 15, 2015)

Wireaddict said:


> I've also seen this problem caused by loose neutral neutral connections at the transformers, meter sockets & in panels.  Ultimately all neutral wires [& grounds] need to end up connected to the center tap in the secondary of the power company's transformer.  Loose connections between the panel neutral bus & the tranny center tap cause the panel neutral potential to "float" instead of being about zero volts with respect to ground & about 120 volts with respect to either [240 volt] hot terminal.  That wasn't your problem but if lights dim or brighten a lot when 120-volt motors or heaters start check voltage between neutral bus & power line in terminals on either side of your main breaker with these devices are on.  I've seen several main breakers develop resistance with age [mainly 100A breakers].  [A weird & rare occurrence that can happen is that a neutral connection opens up in a building & the neutral unbalance fault current flows between ground ground rods &/or cold water pipe bonding to those in neighboring buildings, particularly if they're fed by the same tranny.]



I learned about the open neutral situation personally about 30 years ago when the buried utility opened and did weird excursions in all of the lamps. The repair guy arrived on the scene in less than a half of an hour. When I remarked on how quickly he showed up he responded "We don't want to burn your house down" !!


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## TOOLMASTER (Nov 15, 2015)

i have to check ground often..when you pop a breaker while welding the amprage has a tendency of straying down the line


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## John_Dennis (Nov 20, 2015)

It is a good practice to tighten the terminal screws ground, neutral and hot, in your breaker box annually.  They can become loose over time due to heat expansion and contraction.  All wiring vibrates slightly at 60 Hz which can cause bad connections to loosen and insulation to wear through if it touches a sharp edge.  

Good connections are very important. I like Ideal "B-cap" wire nuts because you can unscrew them easily.  All wire nuts must be the right size and have a metal spring inside.  3M makes some multi-colored wire nuts that have an expanded range that can be very convenient.  Remove 3/4 inch of insulation, twist the wires together with lineman's pliers, trim to 1/2 inch, secure with wire nut. Best practice is to tape wire nut to wire, and tape all plugs and switches.

If you have a Federal Pacific breaker box, replace the entire panel ASAP.  They to not work, and do not provide circuit protection.  Square D, Siemens, GE and Cutler Hammer are the major reputable manufactures of electrical panels.  If you have a different brand, do some research or have an electrician check it out.


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