Low voltage wiring - NEC question

These are either article 725 class 2 or class 1 circuits, depending on the current limiting in the transformer. Class 1 (not current limited) is treated just like regular power circuits. Class 2 (less than 30v, current limited) still requires protection from physical damage.

Lack of enforcement does not change the code. I bet there are some AHJs who would say you do need a permit to install landscape lighting but there is no easy way to enforce it. Bear in mind plenty of people do service upgrades without perrmits and I doubt anyone would say replacing a panelboard does not involve the NEC.

Our Township code says I need a permit for any job costing $200 or more. If I buy a new panel (including a bunch of breakers) for $150 and reuse most of the existing breakers in the new panel (thus staying under the $200), where is the requirement for a permit?

(The main breakers are in the garage back-to-back with the meter, so I can easily kill the power to the panel I'm replacing.)

Perce

On 09/04/05 12:44 pm snipped-for-privacy@aol.com tossed the following ingredients into the ever-growing pot of cybersoup:

My recent experience also.

When I was designing and building a homebrew hard-wired lighting system (still in constant flux ;-), the inspector came over and examined my dimmer panel while it was still on the work bench. He explained what he did and didn't want to see. Seems to me that some decisions/details were a matter of professional preference/judgement and not predictable based exclusively on the NEC no matter how many times I might have read it. I did as he suggested and things went swimmingly.

Picture and description here:

I learned for example, that one can place a load center at floor level. Who would have thunk ! So a load center can be hidden inside a 36" kitchen base -- potentially a design life-saver. (A load center is like an entrance panel except it is fed from the main entrance panel instead of the "street". They are very useful in retrofits as well as large houses).

But he also made me tear down and replace an entire partition wall because I only had 28" instead of the required 30" clearance in front of the proposed location for new load center :-(

.... Marc Marc_F_Hult

Good job, Marc. I do have one suggestion regarding the work in case you ever decide to do a similar project. Consider making each cable long enough to go from the entry point of the cabinet to the opposite end (top/bottom) then back up/down to the connection point making right turns at each point. The result will be neater looking (inspectors like that) and easier to service.

For the benefit of some less experienced than Marc, I also like to leave enough of the outer jacket on NM cables in place so that I can write on the jacket an identification such as "Din Rm Recessed Cans" or whatever. It makes things much easier to service.

Asking for his advice and working with him on various projects will almost always get you more flex room than quoting code. :^)

I was not aware of that one. I know that you need to have certain amounts of working clearance in front of a panel. It never even occurred to me that one could install a cabinet that low though.

Even in small houses, they can come in handy. While redoing my first house, a 1929 "ginger bread" in W Hartford, CT, I needed to install about a half dozen new circuits on the second floor. There wasn't a single grounded outlet in the house. I replaced the ancient, 40-Amp fuse panel in the basement, installed a new meter pan, 200-Amp (what the heck) main panel, added a 60-Amp load center in the attic and replaced all the knob and tube stuff with Romex. I also installed a manual transfer switch for a generator.

The inspector passed my work after one slight change. I had forgotten to install a cut-off for the new A/C compressor. Once that was done we were all set.

We sold the house about a year after I finished fixing just about everything in it.

Heh. I could have warned you about that one. :^)

If you stay under the limit you may well be OK. However, you might also want to inquire about any *special* rules concerning panel upgrades. Many locations insist on a permit / inspection for service entrance upgrades due to the hazards involved.

Some towns and even some electric service providers insist that a licensed electrician complete a service upgrade. I worked on my own plumbing, electrical and other systems for many years but I don't recommend that others do a service upgrade without at least consulting an experienced tradesman.

Note that in most (though not all) cases removing the meter head from the pan kills the power to the panel. I have seen a few cases where this was not so though. Most were illegal connections where some doofus decided to cheat the electric company out of a few dollars a month. Fortunately, most of the DIYers I know are a lot smarter than that.

Actually all the AC wires do reach all of the SSR's on a given side. What isn't clear from the photo graph is the heat sink up the middle (with fins inside and fans top and bottom) divides the cabinet in two with respect to AC wiring.. Because of the need to route the low voltage wiring in an acceptable way up the middle, and to provide separation of low voltage from the AC, no AC lines can cross from one side of the box to the other. If need arose, one could route AC around outside of course. Also, remember this is a switch box

--not a panel-- for which the NEC specifically changed in IIRC 2000 to clarify that low-voltage and household AC can be in the same enclosure when need. Some incoming AC supplies go to more than relay -- hence the pigtails and wire nuts. In a commercial building 20amps x 120vac = 2400 watts of lighting on a single dimmer may be needed, but that would be more than a bit unusual in a residence. As is, there are 60 amps = 7200 watts per side ~ 3X times what is needed.

For some reason I thought that the NEC specified 1/2". Maybe that's a minimum. I dunno. Good idea if its OK. I use a simple IEC color coding scheme and a map/table/diagram.

As I understand it, the 2005 NEC addresses wire label ling and makes certain nomenclature and style a requirement. No more labels like "Joey's old room"

Done that three times now. They'll take me out feet-first from this one ;-)

I knew too and crossed my fingers. As luck would have it, it was the one pre-existing wall in the remodeled space. The width could have been about 29" if I pulled off some wooden moulding, but the inspector wasn't going to give an inch ;-) (Maybe 1/2" he said.)

Marc Marc_F_Hult