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Marc

Receptacle taps

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I'm looking for an allowance to use 14 gauge taps (about 8 inches long) on a 20 amp multi-receptacle circuit, to tie-in the individual 15 amp receptacles.  I've heard of it before but I'd like to confirm it.  I've an upcoming job involving a complete rewire of all general-purpose receptacle boxes on a house.  I'd much rather use 14 gauge to ease the installation.

I can't find a clear allowance for it in the NEC.  All I can find is 210.19 (A) (4), which is freaking ambiguous.

Anyone?

Edited by Marc

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I've never heard of such an allowance except from uninformed doofuses. 

There's nothing in 210.19 that would allow this. 

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You could replace the 20 amp breaker with a 15, but that would likely be seen as a downgrade.

In my part of Canada, for general convenience outlets, we generally use 15 amp circuits and #14 wire with a maximum of 12 duplex outlets or light fixtures per circuit.

For a 20 amp circuit, the max goes up to 16.

This is in the CEC, so is completely irrelevant to y'all. But is a good design guideline to follow.

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Thanks Guys.  Feels good to get that straightened out.

I'm replacing back-stabs with screw connections, feed-thru with taps and replacing wire nuts with Alumicons on the 4 receps within a small bedroom to see if this combination will work before I do the rest of the house (general purpose wall receptacles only).  This 18 yr old house has voltage drops as high as 18% that sometime dropped to just under 100 volts under 15 amp load.  That's about 300 watts of power lost, mostly within recep boxes.

Two sparkies accepted the job (one is sole Alumicon specialist in my area) then dropped out before they started, so I'm doing it.

I know about the COI here but it's a fire hazard and these clients and I have tried for over 2 months to get someone else to do it.

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An 18 year old house has aluminum wiring?

Skip the pigtails and pass thru the screw termination on devices rated for aluminum wire. You'll have a better shot at getting it all to fit in the box.

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My limited experience with Alumicon connectors is that they take up less space than what I had feared. they are actually pretty easy to work with and accommodate inside standard boxes.

 

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6 hours ago, Tom Raymond said:

An 18 year old house has aluminum wiring?

Skip the pigtails and pass thru the screw termination on devices rated for aluminum wire. You'll have a better shot at getting it all to fit in the box.

No.  No aluminum here.  Just bad connections in the receptacle strings.  They add up as you progress downstream.  I figure if Alumicons can fix aluminum connections then they might well fix other poor connection issues as well.

By using taps instead of pass-thru, only the Alumicons interrupt the circuits and they are supposed to be very good connections.

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I bet you will find back stabbed connections are the problem, if what you say, they did not install pigtails, and are feeding the circuit through the back-stabbed receptacles.

Good Marrette-type wire nuts work fine if they are sized correctly and installed right. Connecting more than 3 wires, you will sometimes get one strand that doesn't get crimped by the nut. But you know all this. Good luck with the project.

Edited by John Kogel

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11 hours ago, John Kogel said:

I bet you will find back stabbed connections are the problem, if what you say, they did not install pigtails, and are feeding the circuit through the back-stabbed receptacles.

Good Marrette-type wire nuts work fine if they are sized correctly and installed right. Connecting more than 3 wires, you will sometimes get one strand that doesn't get crimped by the nut. But you know all this. Good luck with the project.

Marc may have known, but I did not.  Now I do.  Of course, at my age I may have known it sometime in the past!

 

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Found out that these receptacles were back-stabbed throughout the house, the receptacle strings are 15 amps instead of 20, and that the strings nearest the main panel had noticeably less voltage drop that the ones further away, making the choice of 15 amp or 20 amp circuits a factor in excess voltage drops.

The consideration being fire hazards from too much heat developing inside the receptacle boxes, today I replaced the back-stabbed connections with taps on two bedroom circuits.  Out of curiosity, I used wing nuts instead of Alumicons and twisted the conductors tightly about 1/2 to 3/4 inch long before torquing the wing nuts as tightly as I could.

The string with the worst voltage drops saw drops reduced from 16 (previously 18) to 11%.

In yesterday's local news was a report about a home that caught fire, causing major damage.  Family was away at the time.  Fire Marshall visited that night and reported that an electric space heater and massage chair were plugged into an outlet situated behind a living room sofa.  He seemed to suspect that the fire started there.

Excessive voltage drops in receptacle boxes do start fires, but there's more factors involved than I thought.

Edited by Marc

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Yes, back stabbed connections are bad enough, but when they are daisy-chained, the bad connections are in series, leading to what you are finding there. I don't know the NEC rule, but here, all outlets must be pig-tailed except the last one in the circuit.

Back-stabbing is allowed for individual outlets but not to feed through. Best practice is to use the screws, using a good stripper that doesn't nick the wire. With needle-nose pliers, form a clean hook 3/4 of the way around the screw in a clockwise direction so that it tightens with the screw.

Years ago I discovered that when you have excessive voltage drop, in my case a bunch of daisy-chained extension cords, the wiring at the low voltage end of the circuit starts to overheat when the circuit is loaded with something like a space heater. In my case, I was walking past the shed and saw wire insulation on fire.

I think as voltage drops, current increases to produce the same power output. That excessive current leads to hot spots and fires.

 

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41 minutes ago, John Kogel said:

Yes, back stabbed connections are bad enough, but when they are daisy-chained, the bad connections are in series, leading to what you are finding there. I don't know the NEC rule, but here, all outlets must be pig-tailed except the last one in the circuit.

Back-stabbing is allowed for individual outlets but not to feed through. Best practice is to use the screws, using a good stripper that doesn't nick the wire. With needle-nose pliers, form a clean hook 3/4 of the way around the screw in a clockwise direction so that it tightens with the screw.

Years ago I discovered that when you have excessive voltage drop, in my case a bunch of daisy-chained extension cords, the wiring at the low voltage end of the circuit starts to overheat when the circuit is loaded with something like a space heater. In my case, I was walking past the shed and saw wire insulation on fire.

Quote

It's the receptacles upstream of the appliance that heat up.  The downstream receptacles are unaffected.

I think as voltage drops, current increases to produce the same power output. That excessive current leads to hot spots and fires.

Quote

You might be thinking of induction motor loads but I'm not aware of any portable appliance loads that use them except very small ones like shaded-pole box fans.

Barring that, voltage-drops act to reduce both the current and the total power developed within the circuit with an increasing share of that power lost to the premises wiring as the voltage-drops get worse.

 

 

Edited by Marc

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