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Posted By: socalclem Parallel vs. Series - 12/02/05 02:47 AM
Im looking for information regarding wiring single-family dwellinging units using "Romex"I was taught to "pigtail" ALL receptacles and switches out: 1- to make the finish side easier and 2 - if a receptacle or switch were to be removed from the circuit, by way of loose connection or the stab-in did not grab a hold and the wire came out, the remaining circuit down stream would remain energized. From my understanding this would be in Parallel.

On the flip side, the new company i work for does not pigtail anything out. We just stab all wires in the back of the devices, for speed.(its all about the money right?) So, using this method, if a problem occurred in a switch or receptacle as noted above, you would lose power downstream. Series?

Are there any Code articles that support wiring in Parallel vs. Series?
Posted By: distributor x Re: Parallel vs. Series - 12/02/05 02:57 AM
If you "stab" all the wires in the back, it is not in series. It is a parallel connection in the device.
Posted By: Electric Eagle Re: Parallel vs. Series - 12/02/05 02:59 AM
Whether you pigtail or back stab, both methods are technically parallel. I'm not going to go into which is better, there are plenty of threads debating this issue if you look around. In a series circuit, you would only have one wire in and one out and if the device is not in use the circuit is broken.
Posted By: ShockMe77 Re: Parallel vs. Series - 12/02/05 03:01 AM
Series circuits have only 1 path for current to flow.

Parallel circuits have more than one path for current to flow.

For instance, a grounded conductor (commonly known as a neutral conductor) is the return path in a parallel circuit and is a current carrying conductor.

[This message has been edited by ShockMe77 (edited 12-01-2005).]
Posted By: WFO Re: Parallel vs. Series - 12/02/05 12:18 PM
I think what he is referring to is the tab of the receptacle itself becomes the series element (which technically it does).

So let me expand on that. Is the tab on a receptacle rated the same as the receptacle? (ie-a 15 amp receptacle would only be capable of passing 15 amps through the tab downstream)

If so, is it legal to wire a 15 amp receptacle into a #12 awg 20 amp circuit in the "backstabbing" manner noted above?
Posted By: watthead Re: Parallel vs. Series - 12/02/05 01:28 PM
It used to be, but not anymore. Now you can only backstab #14 wire on 15 amp circuits.
Posted By: HondaGuy18 Re: Parallel vs. Series - 12/02/05 07:03 PM
I wouldn't stab the terminals at all i mean after a while yur gonna have problems...when troubleshooting circuits in a dwelling half the time it all goes back to those stab terminals. because when u push the device back in the box it sometimes loosens up the stab and makes a loose connecton that may cause arcing..then when trying to find the problem you pull the device back out...and the stab terminal tightens making a good connection thinking you don't have a problem... so i would not suggest the stab in terminals.
Posted By: HotLine1 Re: Parallel vs. Series - 12/02/05 11:02 PM
Basically, series connected devices that a resi elec will encounter are fuses, circuit breakers and switches. Lighting, receptacles, etc., are all wired in parallel.

That's the basic way I explain it to my entry level students at Vo-Tech.

Connect a fuse, breaker, switch in 'parallel' on 120 volt and it will go "BOOM".

John
Posted By: HondaGuy18 Re: Parallel vs. Series - 12/03/05 04:50 PM
Thats true and also the code does not allow a circuit to depend on the device...this meaning don't hook devices up in series..the circuit cannot rely on the device beause if the device fails the whole circuit fails
Posted By: iwire Re: Parallel vs. Series - 12/03/05 04:59 PM
Hondaguy
Quote
code does not allow a circuit to depend on the device

You have been misinformed.

There are two code sections that I am aware of that address the issue you bring up.

One is 250.148 which requires that device removal will not interrupt the continuity of the equipment grounding conductor.

The second is 300.13(B) which requires that device removal will not interrupt the continuity of a grounded condutor that is part of a multiwire branch circuit.

[This message has been edited by iwire (edited 12-03-2005).]
Posted By: electure Re: Parallel vs. Series - 12/03/05 07:36 PM
Quote
If so, is it legal to wire a 15 amp receptacle into a #12 awg 20 amp circuit in the "backstabbing" manner noted above?
WFO, Receptacles with backstabs are no longer made with holes that will accept wire larger than #14. It's been about 10 years since the ones with #12 holes were discontinued. Also, the receptacles state "#14 Solid Copper Wire Only" right on the back.
Posted By: lamplighter Re: Parallel vs. Series - 12/03/05 09:44 PM
I always pigtail the neutral when installing a receptacle. It has nothing to do with series or parallel. (whether or not you pigtail it, it's still wired in parallel) I do it so that the next electrician to come down the pike won't have to deal with breaking the neutral to the rest of the circuit if he has to replace the recept.
If the recepts are part of a multi-wire branch circuit, 300.13 prohibits using the device as a splice anyway.
Posted By: ShockMe77 Re: Parallel vs. Series - 12/04/05 12:17 AM
Art. 300.13 is very important - especially if you value your paycheck and don't want to pay for the customers expensive television set that you accidentally sent 160 volts to instead of the required 120. Oh, and the the other half of the branch circuit won't have enough voltage to operate whatever load it has. Bottom line, splice your neutrals at the receptacle box where the 3-wire homerun is run to, to avoid damaging equipment. There is no worse a feeling than destroying some guys new plasma television set because you failed to give the other outlets upstream a return path to ground.
Posted By: WFO Re: Parallel vs. Series - 12/04/05 01:32 PM
Quote:
"WFO, Receptacles with backstabs are no longer made with holes that will accept wire larger than #14. It's been about 10 years since the ones with #12 holes were discontinued. Also, the receptacles state "#14 Solid Copper Wire Only" right on the back."

Shows my ignorance. I never used the backstabs anyway and haven't paid any attention to them.
Thanks.
Posted By: ShockMe77 Re: Parallel vs. Series - 12/04/05 05:01 PM
WFO, even if you wanted to stab-lock wih #12cu, you couldn't, because the stab-lock terminal is only big enough to (1) #14cu. I agree with you and don't use them either even it is ok to use them since they are UL rated.
Posted By: larryep Re: Parallel vs. Series - 12/12/05 03:38 AM
i use the back wiring but you still screw the wire down. I don't pigtail outlets. If you do get a bad outlet or loose wire and that outlet hardly gets used you would never know it is faulting.by killing everything down stream it would become noticable and fixed quicker.
Posted By: sierra electrician Re: Parallel vs. Series - 12/12/05 03:49 AM
If you pig tail your outlets...the one that is faulty will be the one that is NOT working. The rest of the circuit will not be effected by the faulty device.
Posted By: lamplighter Re: Parallel vs. Series - 12/12/05 03:14 PM
Larry,
If the recept is part of a multiwire branch circuit, the code requires you to pigtail the neutral.
Not doing so can cause 220v. through everything down line.
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