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Rewire of an apartment (AWG question and general questions)

Rewire of an apartment (AWG question and general questions)

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Old 07-24-11, 01:14 PM
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Rewire of an apartment (AWG question and general questions)

Hi all,

I will be rewiring the upstairs unit of a small apartment building I recently purchased.

Basics: it has old K&T wiring which no longer works (frayed covering, open air splices, etc) No access from below unit but access to 6' tall attic space above unit. Walls are plaster but we will be cutting 4' trench on one side of each wall.

Currently the breaker panels for each unit are on the outside of the home (100 amp service for each apartment). I will be disconnecting all breakers except for the one powering the AC condenser unit (too difficult to rerun that line under siding) and installing a 100 amp breaker to run a sub panel from.

The wire will be run (thhn/thwn) through conduit horizontal about 30' and then vertical about 30' to attic space then in between studs where sub panel will be installed.

Questions are: what size AWG for the red, black, and neutral? What size AWG for the ground? What size conduit so as not to exceed 40% fill space (2.5inch 2 inch?)?
 
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Old 07-24-11, 01:36 PM
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2 copper or 1/0aluminum for the Red/Black,White. 6 copper or 4 aluminum for ground. If you use mettalic conduit you can use that as the grounding conductor. 1.5'' conduit should be plenty.
 
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Old 07-24-11, 01:52 PM
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Thank you for the help Justin!

Anything else in the plan seem off or all good other than stapling every 3 feet for my 14awg for outlets, running 12awg for dedicated to bathroom, kitchen, etc?
 
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Old 07-24-11, 01:56 PM
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Depending on your location and the edition of the NEC adopted, items like AFCI and GFI protection for many circuits would be required. Receptacle spacing, dedicated circuits, interconnected smoke and/or CO alarms are other areas you need to familiarize yourself with.
 
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Old 07-24-11, 02:04 PM
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Thank you Pc!

We are still on the 04 NEC code book; We do have to have dedicated circuits for bath (20amp) and 2 for the kitchen (2- 20 amp). Arc fault may not be required yet but still may be a good idea (even at $55 per breaker)- we have to space every 12 linear feet of wall which could get interesting just because of the layout and I can avoid updating to interconnected smoke alarms as long as I don't have to get a building permit....

Thanks again
 
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Old 07-24-11, 02:21 PM
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We are still on the 04 NEC code book
Code cycles are every three years. For example, 1999, 2002, 2005, 2008 and 2011. I would recommend #3 THHN copper for the black, red and white neutral conductors and #8 THHN copper ground in 1 1/4" in conduit. Unless your local building department has amended the code to not require AFCI circuits in the bedrooms, you'll need them.

I can avoid updating to interconnected smoke alarms as long as I don't have to get a building permit....
A building permit may not be required, but I am sure an electrical permit will be. I would recommend interconnected smoke detectors even if they aren't required.
 
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Old 07-24-11, 02:31 PM
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Although smoke alarms might not be required until a building permit is filed, I will ask you a question. How much is the safety of your families life worth to you? Adding smoke alarms now is probably cheaper than a funeral for a loved one.
 
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Old 07-24-11, 03:55 PM
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Thank you again;

Understand what you are saying, but this is a rental building, so it would be the lives of tenants....but I understand what you're saying in terms of liability for a wrongful death....
 
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Old 07-24-11, 04:11 PM
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Smoke alarms may be required in the rental property.
 
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Old 07-24-11, 04:21 PM
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Chances are that the rules about interconnected smoke alarms may also be found in the statutes and regulations that deal with rental properties. You might as well do it now. If it isn't yet required, you may have to do it down the road. Why tear open walls a second time? Add in tenants living in the building and it's a pain.
 
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Old 07-24-11, 06:21 PM
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Add in am emergency light or two, too while you're at it. If they're not yet required yet, they're next.
 
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Old 07-24-11, 09:09 PM
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Thank you again! Not to go too far off topic, but I researched the emergency lights and a middle priced unit isn't too bad...Does anyone know how they get wired in to the rest of the electric? ex: simple install- mount the light and run 14-2 nm to light or are there additional relays, transistors, etc to set it so that it comes on when the power goes out?
 
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Old 07-25-11, 02:43 AM
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Just to clarify, in an apartment unit setting, the smoke alarms are only required to be interconnected within each unit. So all alarms in one unit would go off, but not in other units (otherwise it would cause serious havoc when someone burns toast).

As for the emergency lights they just get wired into any constant power source. The charging/activation circuits are all built in. I got mine at Home Depot for $40 a unit. However there is a very slick wiring option available as well. When you install the smoke alarms, there is a relay pack available that is triggered by the smoke interconnect (full blown alarm panels can do this too). What I did was wired this relay to automatically cut power to my emergency lights (which turns them on) whenever the smoke alarms go off. This provides automatic egress lighting, since most fires do happen at night. Think of it as a bigger better version of the smokes with the little built-in light. The only requirement for setting this up is that the smokes and lights are on the same circuit.
 
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Old 07-25-11, 08:04 AM
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The only requirement for setting this up is that the smokes and lights are on the same circuit.
The emergency lights and smokes should be on the same circut, anyway in case the breaker trips or gets turned off the lights turn on as an indicator.
 
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Old 07-25-11, 06:49 PM
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Originally Posted by Justin Smith View Post
The emergency lights and smokes should be on the same circut, anyway in case the breaker trips or gets turned off the lights turn on as an indicator.
That may be your preference, but I don't believe it's a NEC requirement.
 
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Old 07-25-11, 07:13 PM
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That may be your preference, but I don't believe it's a NEC requirement.
Yup, just my preference. We need more smilies.
 
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Old 07-28-11, 07:03 AM
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Though it's outside your original question, a few other things to consider for a 2-unit apartment:

- Presuming each unit has its own meter, so the tenants will pay their own electricity, you may also need a third meter for "Common Area" electricity. This includes exterior lighting and anything else that doesn't fall within one unit or the other. As the landlord, you'll have to pay those costs. There may be caveats that you offer a 'discount' for those costs - but if the tenants complain, you need to ensure you haven't been making one of them pay for costs that the other tenant uses.

- Completely agree with interconnected smoke detectors. I believe it's required in most locales right now... and if it's not in yours, you might as well do it. Remember, you could be held liable if something happens. There have been a few high profile court cases about tenants unplugging battery powered detectors, then suing when something happens...

- Many locations allow homeowners to do electrical work on their homes that they reside in. Apartments (even if you live in one unit) typically don't fall into this category - and may require a licensed electrician. Especially for a full rewire, you may want to find out what's allowed in your area and ensure you really want to be taking on that liability.

Just some thoughts... good luck!
 
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