Replacing circuits/breakers

npbsurfr

My old house has cloth sheathed wiring and I'm pulling them as I redo each room at a time. During some light fixture add-ons and what not, I’m going to replace some of my old breakers with new Arc Fault breakers.

I have a few questions though. I was talking with my electrician that I use for sub work and he told me that all circuits connected to a new arc fault breaker has to have a dedicated neutral wire per hot wire from the panel. Reason being that if a neutral goes out I would have caused a 220v and blow everything on those two circuits. Also, with the new arc fault breakers it could cause phantom tripping if you share a neutral. I don’t see this as being accurate since the new arc fault breakers attach to the neutral bar in the panel, not the neutral from circuit. Am I wrong?

For example, lets say I add three 6” and three 4” recessed cans, all with romex in a bedroom from the attic. This room also has six outlets currently in rigid conduit. Because of the wattage being used, I should use two hot lines from the panel. If I install two new arc fault breakers can I share a common neutral for the two or is the electrician correct?

Personally, I think he wants the work and is telling me this to throw me off my game. :P

heartlessmcfly

6" high hats... 3 x 65watts = 195
4" high hats... 3 x 50watts = 150

total wattage of lighting = 345 watts = 2.9amps

2.9amps + 1amp per outlet = 8.9amps

You would only need 1 14/2 circuit. Arc fault breakers require a dedicated neutral (ex. 14/2 homerun to panel.). You cannot, CANNOT, put an arc fault breaker on a multi-wire circuit (ex. 14/3). You will not have a 220volt potential if you lost the neutral, your lights and outlets will not work. Its like the same for a GFCI.

Speedy Petey

Where does the "1amp per outlet" come from???

heartlessmcfly

Just a rule of thumb. Easier to figure out for circuitry just using it as a guideline

kbsparky

Whose thumb? The NEC uses the value of 180 watts per outlet, when figuring loads. This does not apply to dwelling unit calculations, however.

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heartlessmcfly

So when u calculate a home...your telling me u base an outlet for 1.5amps? In reality, I would love to see that. I'm not starting an arguement but show me a home in which all the outlets on a circuit are being used drawing 180watts

frenchelectrican

I will make direct and simplé If you did the load demand caluactions it will allready included the recetpales circuits.

That is the bare bone minumim figures.

The recepatles used in genral circuits are figured included with lighting circuits so basically it called general load circuits however there is couple gotcha that will excluded this one is Kitchen and Bathroom both need it own circuits that will be counted seperated.

Any special load requirement will count seperated.

Merci.
Marc

heartlessmcfly

But he is not doing a rough in from scratch, just adding onto. W/e idc

frenchelectrican

heartlessmcfly.,

Basically when you add the receptale to the exsting circuit I still count to make sure it will not go over the limit and you have to verify which circuit that is served as long it not from any restricted circuits. { as I posted above }

Merci.
Marc

heartlessmcfly

I concur

kbsparky

Apparently you did not read my entire message: I questioned where your so-called "rule of thumb" originated, since the NEC uses 180 watts per outlet on load calculations for non-dwellings. I never saw any 1 amp per outlet mentioned in the Code.

For dwelling calculations, the load calculations are based on square footage of the structure.

__________________
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frenchelectrican

I wrote it in bleu that the key word and that will covered in the load caluations .

Merci.
Marc

Speedy Petey

No, not at all.



I don't "count" receptacles as anything in a residence. This is what I was referring to:
NEC 220.14(I) Receptacle Outlets. Except as covered in 220.14(J) and (K), receptacle outlets shall be calculated at not less than 180 volt-amperes for each single or for each multiple receptacle on one yoke. A single piece of equipment consisting of a multiple receptacle comprised of four or more receptacles shall be calculated at not less than 90 volt-amperes per receptacle. This provision shall not be applicable to the receptacle outlets specified in 210.11(C)(1) and (C)(2).

220.14(J) Dwelling Occupancies. In one-family, two-family, and multifamily dwellings and in guest rooms or guest suites of hotels and motels, the outlets specified in (J)(1), (J)(2), and (J)(3) are included in the general lighting load calculations of 220.12. No additional load calculations shall be required for such outlets.
(1) All general-use receptacle outlets of 20-ampere rating or less, including receptacles connected to the circuits in 210.11(C)(3)
(2) The receptacle outlets specified in 210.52(E) and (G)
(3) The lighting outlets specified in 210.70(A) and (B)