electrical work in an old house

[May]

Hi guys.

My husband and I want to work on our attic (about 400 sq feet) which has never been finished before. we want to make a master bedroom with a bathroom and a closet. There is a circuit on attic now, 3 way switches on the stire way to control one light, 2 other lights which are not connected with any switch. 2 or 3 receptacles. We want to use a window AC, and we bought a whirpool tub for the bathroom. Here is my plan

3 circuits totally, one for AC, one for whirlpool, the third one for bedroom, bathroom and closet and outdoor. one 3 way switches in stairway to control one light. another 2way switches to control 2 lights in bedroom, one smoker in bedroom. one indoor 2 way switch for outdoor light.3 lights above the mirror in bathroom. exhaust fan in bathroom. one light for closet, serveral receptacles acording to code.

Is is correct to divide the circuit as I said? or is there a better way to divide them?

According to watt, AC, whirlpool both can use 15 amp circuit. the third one use 20 amp circuit. should I all use 20 amp circuits just for safety reason?

Thanks! May

[Pete C.]

Suggest you need to consider a whole lot more than just how many circuits for your project.

I'd be particularly concerned structurally with putting a whirlpool tub that could easily weigh 1,000# full in the formerly unfinished attic of an older structure. You also need to consider building code requirements for egress, etc.

As for electrical, I would never bother installing a 15A circuit for much of anything these days. Even with current high copper prices you won't save much with 14ga wire vs. 12ga wire and the breakers cost exactly the same.

You also need to watch out for GFCI and AFCI requirements as you'll need GFCI for both the bathroom and tub, and AFCI for the bedroom. You may also need to make significant upgrades to the rest of the house electrical to meet current codes if you do a large remodel like you're indicating.

Pete C.

[May]

Thanks for your quick reply!

I am going to get a permit before I do the electrical, I definitely won't risk the house without inspector's check( especially I am just a beginner). As for upgrades the rest of the house electrical, what I heard is the inspector will only check the new added works, originally, we want to hire electrican, but that just costs too much for us. even from the quote they sent to us, there is no change about the existing electrical. So i am not sure I will be asked to do that.

[hallerb]

Bath DEFINETELY needs seperate 20 amp GFCI circuit. Probably for code but DEFINETELY to minimize breaker trips.

hair dryers and curlying irons take lots of amps

if your main brreaker cabinet is full think about a sub panel for the addition

what kinda hot water tank do you have, you will likely need a second or much larger one for the whirpool tub

[No]

And - If its an installed Jacuzzi tub with a plug for the motor, and the motor will be relatively inaccessible (Like behind a caulked in tile access panel) then use a GFCI breaker, not outlet. It makes doing a re-set much easier.

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[RBM]

If you're really going to try this by yourself, you should get a book to familiarize yourself with current electrical codes, as well as contact local building dept regarding local codes such as smoke detectors. As the others have said, in the US all bedroom wiring must be afci protected. A 20 amp dedicated circuit is required for the bathroom, which could be used for the tub as well if its total load is less than 10 amps. The A-C will require a dedicated circuit as well and at least one circuit for lighting and outlets

[John Grabowski]

The bathroom requires a separate 20 amp circuit and it cannot feed anything else. You can use one 15 (Or 20) amp circuit for room lighting and outlets, but I prefer to use a separate circuit for outlets in case a breaker trips you still have either the lights or the outlets on. You should look at A/C units now to see how much juice you will need. The attic will be much hotter than rooms down below so you will need a good size air conditioner to handle the heat load. In any case use a 20 amp circuit minimum. Normally I install one 20 amp GFCI receptacle for hydromassage bathtubs without heaters. If you are getting one with a heater (Recommended) you will need an additional 120 volt, 20 amp GFCI circuit. For convenience you can get GFCI switches and mount them in the wall so that you won't need to open up the tub access panel to reset them.

Since you will be doing your own wiring, I suggest that you get a copy of the National Electrical Code (NFPA 70) and read the applicable sections for your renovation.

John Grabowski

[Goedjn]

I would ignore the existing circut entirely, and bring up 60 Amps/240V to a sub-panel.

Then you need

1 20A circut for the bathroom outlets, (GFCI) 1 20A circut for the bedroom outlets, (AFCI) 1 20A dedicated circut for the AC 1 20A circut for the lights everywhere 1 20A circut for the whirlpool (assuming the structure of the house can take it) And enough extra power to run the chair-lift, when one of you breaks your fool leg and can't make it up to your new nest, unassisted.

If you're ever thinking about a kitchenette up there, go with 75A to the sub-panel.

[John Grabowski]

The subpanel is a good idea. It can save you a lot of time running a bunch of cables to your existing panel and it could make it easier to pull circuits in the future down to the floor below.

[Bud--]

If you get the NEC, "NFPA 70A: National Electrical Code Requirements for One-and Two-Family Dwellings" would probably be better than the full NEC. It (I presume, I haven't seen one) removes huge parts of the code not relevant to housing that represent confusing clutter.

I would recommend a book on wiring over the NEC because:

the NEC is written to be a reference, not a learning text or a how-to-do-it manual; relevant sections for a simple task are all over the code

it can be difficult even for electricians to find all the relevant sections for a task; a good electrician may be someone who knows where to find the rules more than one who "knows" the rules

it is not always clear what the words in the NEC mean in the real world without having done/seen the relevant wiring (one reason why NEC handbooks are useful)

it is written in codeese which is not the native language of mere mortals (but can be effective to convey a precise enforceable meaning)

IMHO becoming familiar enough with the NEC to use it is a very steep learning curve

bud--

[Budman]

Hi May,

What makes you think the existing structure (i.e. framing) is strong enough to carry the additional loads imposed by finishing it? Hopefully you have already worked this out, but I see a lot of people trying to finish attics without considering the structural implications (especially in older homes).

The electrical work is usually the easier part.

Budman

[Pete C.]

Exactly, lest the lovebirds hop in the new whirlpool tub to celebrate the completed project and find themselves on the express elevator down a floor or two.

Pete C.