[Stubits]

I am in the planning stages of an addition and am considering electrical needs. I am sure our architect will get to it at some point, but I want to make sure there's sufficient room in the panel.

The addition is small, just 10'x5' on three different floors. On two of the floors the addition will function as a mudroom and on the other more of a reading nook/closet. On each floor, one of the 10' walls is filled with floor to ceiling cabinets. How many outlets am I going to need on each floor? I know/understand the 6'/12' rule, but would appreciate any insight as to how that applies to floor to ceiling cabinetry. What is usually done with floor to ceiling cabinets? Also, does the 6'/12' rule even apply as these are more hallways/pantries/closets?

Additionally, we will adding up to 4 recessed lights per floor (50 watts per light), three exterior lights and 2 exterior outlets (one will power up to a 600 watt transformer).

So, how many circuits would you all suggest and how many are required by code? Overall, there will be between 6 and 9 interior outlets, 2 exterior outlets(with one 300-600 watt transformer), 3 standard exterior light fixtures (100 watts per), and 12 recessed lights (50 watts per). Not including the interior outlets, that is 1500 watts combined. I know a 20 amp circuit can handle between 2000 and 2400 watts, so even if everything was running at once I'd still have between 500 watts and 900 watts remaining. So,I guess the question is, how many circuits would you suggest? Can I get by with 1 20 amp circuit, or is it just way too much?

On a related question, after the addition we will be adding a bathroom and renovating another (they will share one common wall). They are relatively small bathrooms, less than 50 sq. ft. each. We will be adding electric radiant in floor heat to both bathrooms. As the radiant heat is not placed under the tub/shower, vanity or toilet, the combined area for radiant heat between both bathrooms is less than 50 sq. ft. The instructions for the product call for a dedicated 20 amp circuit. The instructions also indicate that 150 sq. ft = 15 amps. So, would it be problematic to have the radiant heat for both bathrooms on 1 circuit? Both bathrooms together would use less than 5 amps.

Thanks for any insight!

[Missouri Bound]

Your questions are more thorough than most of the answers here. I think you know more than any of us can tell you. Just keep the lighting, the outlets and the radiant heat on separate circuits. You already have figured out the loads so you pretty much have it figured out. The NFPA offers a free online NEC book if you are interested in reading it. NFPA

[mirlyn27603]

All rooms, even mudrooms follow the 6/12 rule. A true hallway is even required to have an electrical outlet. You didn't say what state you are located. Some states require a 180va calculation per outlet. The full wall shelving does not exclude you from required outlets. They can either be installed in the cabinets or in the floor along the wall line in front of them.

In terms of load, 1 15 A circuit should be suitable.

[stanfortyman]

All rooms, even mudrooms follow the 6/12 rule. A true hallway is even required to have an electrical outlet. You didn't say what state you are located. Some states require a 180va calculation per outlet. The full wall shelving does not exclude you from required outlets. They can either be installed in the cabinets or in the floor along the wall line in front of them.

I'm going to have to disagree with this. A true mud room does not necessarily fall under the 6/12 rule found in 210.52(A), as most would not consider it a similar room to a "kitchen, family room, dining room, living room, parlor, library, den, sunroom, bedroom, recreation room".
Typically though a mud room does wind up getting more than enough receptacles so the point is rather moot.

Also, built in cabinetry that truly goes from floor to ceiling (or at least ~6') is also not considered "wall space" by the definition of the wording in 210.52(A)(2).
Open shelving is usually another story though.

This is only my opinion based on what my experiences are.

[Stubits]

Thanks everyone! This is great information all around. Very much appreciated!

Stan- I really value your response. I've followed the forum long enough to know you know your stuff and are well respected. Plus, I think you're in MD, right? I am in DC.

So, what makes a mudroom a mudroom, officially? Or is it up to the inspector? Is a mudroom treated as a closet, that is to say,

Regarding the built-ins, are they treated in the same way a door or a fireplace is?

So, based on the above load, lights and outlets, can I get by with (1) 20 amp circuit?

[stanfortyman]

The mud room call will have to be a local call. Thing is, put a couple of receptacles in and don't worry about it. You'll be glad you did.

The cabinets would likely be a local call as well. As long as they are truly cabinets with doors IMO they are not wall space. I know kitchen "pantry cabinets" are treated this way.

If I were you I'd put the lighting on one circuit and the receptacles on another. I do not do this religiously, but I think here it is a good idea. I think you do have enough lighting going in to justify it.

[Stubits]

Excellent. Thanks! I'll definitely throw in a couple of outlets, but following the 6/12 rule seemed excessive given the room's use. I figured there must be a way to handle built in cabinetry from a code perspective, although it is a moot point if the room is deemed a mudroom (can't see why it wouldn't be).

Do you have any thoughts on the radiant floor question I asked above?

[stanfortyman]

Oops, sorry, I didn't notice that one.

You will be totally fine on one circuit.

The 10 watts/sq ft is typical of underfloor heat like that.

Do the thermostats have the built-in GFI protection? Some do which will save you the cost of a GFI breaker or device.

[Stubits]

Awesome. Seemed really silly to waste 2 circuits on like 5 amps.

Back to the lights/outlets from earlier. I could get away with 1 circuit, right? Would just be better with 2?

Thanks!

[Stubits]

Bump

[stanfortyman]

I would still do two. Unless panel space is at a premium.

Separating the lights and receptacles is not mandatory though if you don't want. You can break it up into areas instead.

[Stubits]

Space in the panel might be an issue. Although if it's OK to put the radiant heat from both baths onto one circuit I should be just fine.

[Missouri Bound]

The reason I suggested that you use separate circuits for lights and outlets is if by chance you overload the outlet circuit, you wouldn't be in the dark. (Unless your lamps are plugged into the outlets, of course)