I remember the exact moment it happened. I was in the fourth grade; we were learning long division. It was when I ceased to comprehend math. It was a feeling of being left behind, and a frustration so intense that my eyes would start watering and my ears would close. It wasn’t making any sense, so I stopped trying.
Electricity is a little bit like long division, but now that I am no longer in the fourth grade, (no more waterworks or shutting down) I am a little more open to understanding the unfamiliar. Electricity, you are mine!
Side note: I almost didn’t study architecture because I thought it would require complex math – regularly. Wrong. Although you have to take (and pass) geometry, trig, and calculus, while studying architecture, you hardly use math, other than adding and subtracting, on an average day. We architects have a couple of mathematical ‘rules of thumb’ in our pockets, but for the most part we leave the complex structural calculations to the engineers.
There is however still some math required in wiring a home…
Here’s a fun word I never knew: Totting (v.) – the act of adding. Totting sounds more like a British hamlet, than a mathematical term, which is probably why it appeals to me. Anyway, to compute the load on a circuit, one must “tot” up the amperes that every appliance and fixture draws from the circuit. Often the amount of electricity required to operate a device is noted in watts, and you must convert the watts into amps by dividing the wattage by voltage (typically 120 or 240 volts).
40 watt bulb / 120 volts = .3 amp OR 1500 watt hair dryer / 120 volts = 12.5 amps
You cannot exceed the total amperage allowed by a circuit otherwise you will short a fuse. According to Ed, you can put about seven outlets on a circuit before it will be overloaded, and even more light fixtures because they are low voltage.
A circuit is comprised of Romex – a plastic cable that houses copper wires, which provide electricity to all outlets, light fixtures, and appliances. Generic Romex is also called N.M. cable, or non-metallic sheathed cable. Each circuit begins at the electrical panel, wends its way through walls, and ends up feeding outlets, switches and fixtures in each room.
There are many different sizes of Romex, which determines the amount of amperage available. The one used most often in residential wiring is size 12ga – the yellow cable – which provides 20 amps. 14ga is allowed by code, but there is a consensus within the electrical community to move to 12ga. It isn’t significantly more expensive and it provides more amperage.
The difference between, for example, 12ga and 12-3ga is a third (red) wire, which allows for a three-way switch – if you want to operate a fixture from two different switches.
There is a specific term used in wiring worth knowing: homerun. It refers to a dedicated wire running from the first device on a circuit, to the main panel. Some large appliances are on their own dedicated circuit (wire) so at the switch board there will be a breaker solely for that appliance.
Before we started running Romex, we had to locate outlet boxes, light fixture boxes, and switch boxes in every room. There are standard heights and locations for all electrical equipment:
After locating we then wired all electrical boxes.
Telecommunications are also under the purview of the electricians, which means they run all telephone, internet and satellite cables.
A few important electrical code requirements:
- Wall receptacles need to be within 12 feet from each other.
- Receptacles in ‘wet rooms’ (kitchen and bathrooms) need to be GFCI (ground fault circuit interrupter) receptacles, which prevent electrical shock.
- A light fixture at every exterior door.
- 30” x 36” workspace in front of electrical panel.
If you would like to learn how to wire a receptacle or light switch I found this video very useful:
Oh yeah, we also finished framing this week and installed all the exterior doors and windows. No big deal.
Last we left off, the carport was still roofless. No longer! We had to rent another crane to help lift the massive beam 17 feet in the air. It is worth the money. We were trying to figure out how to lift it into place via scaffolding but it was becoming very dangerous.
While Gil, Juan, and Weasel were working on the carport, Greg and Leaps were inside building the interior walls at the kitchen/panty/entry and in the master bedroom.
Windows & Doors
In preparation for the door and window Installation Greg added the 2×6 pack out around the interior perimeter of all openings.
On Wednesday (a week ago) the guys from Sierra Pacific delivered our door and window package. There were many and they were MASSIVE. It took all the guys to move most of the large windows and doors.
It took the crew two days to install everything, including fixing the “shipwrecks” when the big trapezoidal windows didn’t fit.
Next, the guys applied Bituthene, a self-adhesive, black waterproofing membrane at the sill of all the windows.
We still have to get the corner windows custom glazed. Sierra Pacific wouldn’t warrantee them with out a corner mullion, so we are hiring a local glass company to cut and install them.
Lastly, we had Cranky Franky pour the concrete pan for the guest shower. Frank had never installed a linear shower drain before, let alone a monoslope shower pan, so he had some growing pains. But, the building inspector approved it, so we are home free.
Northern New Mexico Eye Candy
I love these doors.