Series or parallel

runronno

I was just wondering what preference anyone has when hooking up a circuit of outlets, Do you hooked them in series or parallel them with pigtails. I always did them in series but my instructor said to parallel them so if you have a problem with one you won't lose the string. Is there a correct answer to this or just preference. Ron

jerryh3

Watch using the words series and parallel when dealing with househould receptacle circuits. Technically, they are always wired in parellel. I think the use of pigtails is personal preference of the installer.

rgsgww

I like to use pigtails, but if I have no space in the box, I won't use them.

joed

Using pigtail won't prevent losing one receptacle from taking out the others. Instead of having two screw connections you now have one screw connection and one wire nut connection that can fail. I trust screw connection better than wire nut connections. Plus in Canada wire nuts count for box fill.

chris75

I trust both equally, its all in the mechanic installing the stuff that you cannot trust.

hpp58

If the circuit is a multiwire branch circuit, you must use pigtails for the nuetral wire (as per 300.13 (B)).
I got in the habit of wiring all my nuetral connections that way.

jamiedolan

Do you think that I should go change all of my outlets that are not pig tailed to having pig tails since everything is running off of MWBC now?

Jamie

InPhase277

Jamie, in your situation, the MWBCs don't pass through the outlet box. At your receptacles, the circuit is a regular circuit because the MWBC splits at the junction in the basement. The post you are responding to is meant for a setup where the neutral of the MWBC can be interrupted by removing a receptacle. This cannot happen in your
system.

jamiedolan

Oh, I see why there is more danger to a MWBC if the neutral connection is run via the outlet and it can be disconnected there. I am thinking I will run WMBC for my kitchen as well since there will be a number of circuits there. However, I will do the same sort of setup as the basement and will junction everything in the attic and then just drop down the final connections to the kitchen.

Jamie

J. V.

I would not use MWBC's unless I had to. Why do you want to use them in the kitchen? You can install all the required receptacles on two single branch circuits. Do you have a special need for the MWBC's?

jamiedolan

Just conduit fill / derating issues. I was planing atleast 3 circuits for 120v outlets, plus a dedicated outlet each for the microwave, frige and disposal. A 240 circuit for the oven, and one for the espresso machine.

Plus I need to tap off of the same runs of conduit for new wiring for 3 bathrooms and for my upstairs bar outlets.

So I need as much space as I can get due to the wire limits due to derating factors that apply.

Jamie

rhenri89

If it where me i would hook them up in parallel

Atroxx

When you wire up receptacles using pigtails, you aren't subject to the resistance of the receptacle. This can lower your power bill by a fair margin if you do it on all your receptacles throughout the house.

I don't know exact numbers, but if you think about it the resistance across the ear of a receptacle is much lower than the wire you feed it with. So let's say for the sake of argument that the resistance of a receptacle ear is 2% higher than the resistance of your wire. After 10 receptacles, that resistance adds up to be 20% more than the branch circuit wire. The more resistance you have, the higher your power bill is.

And also, I agree that a screw head installation can fail just as easily as a wire nut can if done improperly.

Yoyizit

50' of #14 AWG copper Romex carrying 4A =4W, about as much as a clock. With no pigtails, 5W. That's a savings of ~9kWh/yr.

InPhase277

Now all I got to do is find where I put those darned Kelvin clips...

I seriously doubt the resistance of a receptacle is measurably different than that of a wire nut splice. I mean, it may be measurable in a lab under controlled conditions. Which means it is so small as to be insignificant in practice.

In fact, I might even venture that the resistance through a receptacle may actually be less than that of a wire nutted splice, because the terminal contacts the conductor on both sides, pretty much doubling the surface area compared to that available in a twisted splice, not counting the steel spring of the wire nut.