electricallighting
I have a mix of lightly used track lighting pieces that I got second-hand. The connectors seem to different brands, but all fit with each other. (Same profile.)
My question is about the contacts on the connectors, that connect the bus bars of one piece of track to another piece. Some appear to be bare copper, others brass, others appear to be aluminum, or maybe tinned copper? Do I need to be concerned about long-term compatibility here?
Without being able to see the cables as they enter the cabinet; or the ability to touch or trace them, here is what I assume is going on.
A typical single split phase service is made up of 3 wires. Two ungrounded (hot) conductors, and one grounded (neutral) conductor. The ungrounded (hot) conductors will connect to the main service panel through a disconnect (usually a large breaker), while the grounded (neutral) connects to the neutral lug. The neutral lug will be bonded (electrically connected) to the neutral bus bar, and all grounded (neutral) branch circuit conductors will terminate at the neutral bus.
This conductor is used to connect the grounding electrode (ground rod, etc.), to the grounding bus in the panel. All equipment grounding conductors will be connected to this bus.
The bonding jumper is used to bond (electrically connect), the un-energized metal parts of the panel to the grounding system.
Since it appears that (what I assume is) the grounding electrode conductor terminates at the neutral bus, I'm also assuming that this is the main service disconnect. This leads me to believe that the neutral and grounding buses are bonded (electrically connected). In which case, technically, grounded (neutral) branch circuit conductors can terminate at the grounding bus.
So you have two options:
Terminate the grounded (neutral) from the new circuit to the grounding bus.
Move the green wire that is terminated on the neutral bus, to the grounding bus. Then terminate the grounded (neutral) from the new circuit, to the freed up slot on the neutral bus.
Since this is a new circuit, it has to be installed to current code standards.
National Electrical Code 2011
ARTICLE 250 — GROUNDING AND BONDING
VI. Equipment Grounding and Equipment Grounding Conductors
250.140 Frames of Ranges and Clothes Dryers. Frames of electric ranges, wall-mounted ovens, counter-mounted cooking units, clothes dryers, and outlet or junction boxes that are part of the circuit for these appliances shall be connected to the equipment grounding conductor in the manner specified by 250.134 or 250.138.
Which in this case means installing a NEMA 14 receptacle for the dryer, and a proper grounding conductor.
You'll have to follow the dryer manufacturers installation instructions for upgrading to a 4 wire cord. For more information see this answer, and this answer.
Since you've said that you're already using 4 wire cable, you'll simply have to terminate the grounding conductor in the cable to the grounding bus in the service panel. Then connect the other end of the grounding conductor to the grounding terminal in the dryer receptacle.
You'll also want to be sure that you're using the proper size breaker and conductors. In the case of a dryer, you'll typically use a 30 ampere breaker and 10 AWG conductors (depending on the length of the run). However, you'll want to check the dryer manufacturers installation instructions to verify this.
No. First as you have mentioned there is line and low voltage. If you are not sure what to choose from pick line voltage - you can always put it on a dimmer to get what you need. The low voltage tracks in my opinion are junk because they only allow a certain amount of light, and the transformers go out or hummmm after a while. That is just my opinion on this - people will say you can find more selection of light bulbs with low voltage and there are special circumstances where this is right but you can order a lot of stuff easy on the internet now.
OK back to your main question. No again. In the US there are three main types. See the picture below.
Get a ladder and take a look at your track or take a picture on your phone. The Juno tracks I have seen have been j-style but you need to look because they are a huge maker and I am sure they have made each style.
Best Answer
This is exactly what I was trying to say before, (what you found on Nora's spec sheet) admittedly not as clearly as I should. These manufacturers are not going to put their products at risk with such a fundamental flaw. I have seen bus work in load centers over the years and learned that all those different colors mean little of nothing. People will often think that just because a contact metal is silver in color, it has to be aluminum. These manufacturers know very well the dangers of oxidation and specifically the problems with the oxidation of aluminum. They avoid it like the plague. Additionally, they know the results of mixing dissimilar base metals and the electrolysis that if can cause. This, they avoid as well. The problem gets worse: The metal ‘copper’ alone or in high concentration is actually a problem also because although it is an excellent conductor it alone is too soft to stand up to the rigors of an electrical contact surface. Therefore, manufacturers combing copper with other alloys to make it stronger. Every manufacturer has their own proprietary mix and the resulting look or color is different in every case. They pay metallurgist big money to figure these things out. You can be quite sure of this; the contact metal, you speak of, will stand up the rigors required and at the same time do an efficient job of conducting the electricity necessary without harmful reactions between metals. I hope I made this more clear. P.