Neutral Wire

[felixn@pacbell.net]

Can someone please help me with the following question.

I am trying to convince a home owner and his architect to use a 3 wire conductor in their new construction. Mainly this is because of dimmers that require Load, Line, Neutral and Ground. Can you please tell me what are the compeling reasons why new constructiosn should include neutral wire? And is the typical new construction today using a neutral wire or not?
Thank you very much.
Felix

 

[George Stolz]

I am trying to convince a home owner and his architect to use a 3 wire conductor in their new construction. Mainly this is because of dimmers that require Load, Line, Neutral and Ground.

A neutral can be present at dimmer locations without the use of three-conductor cables. It would be more approriate to specify that a neutral should be present at all switching locations, than to specify three-conductor cable be used exclusively.

One common method of threeway switching actually uses a single three-conductor cable and does not contain a neutral conductor - the white conductor is reidentified to call attention to it's use in this manner.

Can you please tell me what are the compeling reasons why new constructiosn should include neutral wire? And is the typical new construction today using a neutral wire or not?

In general, the neutral conductor is only present if power is brought to the switch first, which (unless specified otherwise) is entirely up to the installer of the system. In some cases (such as when installing a circuit for a disposal), it is more beneficial to wire such that the cable from the panel is brought to the receptacle box first, and then another cable runs to the switch. This allows for a future insta-hot to be installed later, unswitched, without having to fish more cables in the walls (210.23 permitting).

In the 2008 NEC, it appears that a neutral conductor will be required to be brought to all switching locations, and that dimmers will be redesigned to not use the EGC as a stand-in for the neutral conductor, as they are currently UL-listed to do.

 

[winnie]

You are not an electrician, and forum rules prohibit DIY assistance. It sounds to me like you are specifying stuff at the design level for an electrician to install, but if this is not the case, then I urge you to get an electrician involved.

90% of the 120V wiring installed in a home has the neutral present. The only common situation where the neutral is not present is in 'switch loops', where the power feed goes directly to the lamp, and only the 'hot' and 'switched' conductors are routed from the lamp to the switch. Placing a requirement in the plans that all 'switch loops' be run with an extra conductor to provide a neutral should result in minimal change in labor and materials cost.

In fact, it is so cheap to do so that many electricians do something similar as a matter of good design. It is quite common to run an extra conductor between the switch and the lighting outlet to allow for the possibility of ceiling fans. The extra conductor makes it easy to have a separate control for the light and the fan.

Having the neutral present at all points in the circuit, including at switch loops, provides for extra flexibility; both in terms of future expansion and in terms of control devices which may be used. The _potential_ benefit must be balanced against the _small_ additional cost.

-Jon

 

[felixn@pacbell.net]

neutral wire

neutral wire

thank you both for your replies to my post. I appreciate your comments very much. I am not an electrician but I do understand electricity and have a degree from many years back. I am sure with a bit of strugle I can recall relavant issues.
I do have a follow up question that is of great improtance to me.
You stated that an electricial can bring in a neutral wire at the dimmer box without re-wiring the entire house. Can you please help me understand this more? At least to the level that I can specify to the electrician?
Thank you so much
Felix

 

[George Stolz]

At least to the level that I can specify to the electrician?

The electrician should be able to understand the instruction, "Please provide a neutral conductor at the switching locations for all light fixtures."

 

[George Stolz]

Felix, if the house has not been wired, why would it require re-wiring the house?

Is this old work or new work? At the new work stage, you can require anything you want and the electrician can determine if it warrants added cost or not, and feasibility.

 

[felixn@pacbell.net]

neutral wire

neutral wire

Sorry about dragging out all my unleasant detail.
This is a remodel where the owner took the old house down to foundation and starting from scratch. However, electrician has already wired most of the house, sheet rock is not up yet. His and architects claim is that neutral wire is not typical and not required by code. I am trying to convince them to change some of the wire before the sheet rock is put up.
I think I am doing the right thing.
F

 

[felixn@pacbell.net]

more: on neutral wire

more: on neutral wire

Just in case either of you interested to read more of the background....
I formed a new company that specialises in residential home automation. I have a lot of digital expertise and system capability. Many of the components I use, like Insteon, Z-wave, ZigBee, UPB require their devices to have a neutral wire. Furthermore, i suspect that having reduced noise and ballance on circuits that eliminates surges is a good thing for a house full of sensitive electronic equipment. Thus, I hope to have better understanding.
Thank you for your time.
Felix

 

[don_resqcapt19]

Furthermore, i suspect that having reduced noise and ballance on circuits that eliminates surges is a good thing for a house full of sensitive electronic equipment

How does running a neutral to all locations have any effect on that?
Don

 

[winnie]

Many of the components I use, like Insteon, Z-wave, ZigBee, UPB require their devices to have a neutral wire.

This is because these devices require power that is independant of the power actually going to the load.

Some devices which require power get it by 'tapping' some of the juice flowing through the load. You will see devices which specify that they can only control incandescent lamps with a minimum of 40W load, for example.

Other devices actually permit a very slight current flow to the EGC, essentially using the EGC as a bootleg neutral. UL permits this as it is a very small current, but IMHO this is a bad idea.

Furthermore, i suspect that having reduced noise and ballance on circuits that eliminates surges is a good thing for a house full of sensitive electronic equipment. Thus, I hope to have better understanding.
Thank you for your time.
Felix

Having the neutral available at the switch will have no significant effect on the noise and balance of a properly wired circuit.

In a properly wired circuit, all current flowing through one conductor will be balanced by current flowing through an adjacent conductor. This _might_ be a 'hot' and 'neutral' pair...but it could just as easily be the 'hot' and 'switched hot' pair of a switch loop. As long as current (and conductors) follow matched pairs, then the circuit will not have significant loop area to couple EMF out or in to the wires.

There are situations found in _improperly_ wired systems, where a neutral is 'stolen' from a separate circuit. Current flow no longer follows nice adjacent balanced paths, but instead has large loops. This loop area can both couple EMF out and can couple noise into the circuit.

-Jon

 

[felixn@pacbell.net]

Neutral wire

Neutral wire

Given all that you explained about usage of neutral wire, what is the future in your point of view in the US home development? Will new constructions be required to have a neutral wire throught the house by code at some point? If so, what would be the main reason for such requirment? This is a very important issue for me considering many Architects and Developers I have spoken to continue to build or do complete remodels without specifying neutral wire requirment.
Thanks
Felix\

 

[George Stolz]

Felix, I think you're too late to avoid a backcharge from the electrician if he has already completed most of the wiring. There is no such requirement in the NEC.

404.2(A), exception, explicitly states that neutral conductors are not currently required to be present at switching locations. As I mentioned before, this may well change in the next cycle, but currently it's not required.

If the homeowner is going to purchase equipment (from you, through you, around you), then the electricians will need the specs for that equipment. If not, and you're trying to prepare for what-ifs, then the homeowner should decide how much they are willing to spend to prewire for that equipment.

It will likely be cheaper to pay a change order now, to redo the work without drywall, than to fish in later on a seperate trip - you're right there.

If the homeowner is only marginally interested in the equipment in question, then there is no reason to change out the work completed.

 

[Pierre C Belarge]

Why are this guys questions being answered? He claims to have started a company that he seems not to really understand the fundamentals of. He should hire a qualified person to work his company and not depend on the forum to answer his questions.

 

[LawnGuyLandSparky]

Whatever the case is, it is clear the OP is NOT an electrician, and I believe it's a stretch for him to claim he's an EE as well.

Sounds more like a salesman.

 

[felixn@pacbell.net]

neutral wire

neutral wire

Thank you very much for your explanations George and Jon. It appears I got the dogs out after me. I guess it gives them some type of gratification to call me a salesman. I was very impressed with this forum until those two posts. I am not an electrician nor a salesman. Since I am not interested in a personality contenst I won't be posting to this thread again.

THanks again for your kinds responce.
Felix

 

[LarryFine]

Felix, in the hopes that you at least return to read this thread one more time, I'd like to throw in a little opinion or two. Not all home-automation equipment requires neutrals; often, it's merely for the LED's.

Quite familair with home automation myself, I thought you were headed there when I read your initial post, and was ready to mention that the fancier devices are the only dimmmer types that normally require neutrals.

Standard X-10 and many other PLC devices don't require neutrals, as they receive tricle current through the load. That's why Ul requires the obnoxious disconnect switches for safe bulb-changing and such.

To answer your questions directly, the only compulsion for avoiding switch loops that don't bring neutrals to the switches is when it is requested before the work commences. Just specify it in the plans.

If you are recommending incorporating neutrals at all switches in this work, and doin so would require redoing work already done, you and the homeowner need to decide if it's important enough to pay for the changes.

There's no way to claim that it should have been done as a matter of practice, or that it should be re-done at no charge, unless it was requested before the work began, although it's my usual practice.

In the future, you'll have to get this requirement into the contract early on. If the electrician says doing so will cost a bit more, because it's different than his usual methods, so be it. 3-wire to fan boxes is a must.