wiring/switch problem

I just installed a simple chandelier to an existing(i.e. pre-wired, capped, never used but presumed wired OK in a modern house) ceiling outlet as follows. A to red, B to white(geyish) and ground(uncovered) to orange in ceiling.

A&B are from the chandelier base and are a pair of wires (+ & -) with no differing markings, so presumably interchangeable.

Tested in ceining with phase tester. Red was hot. Hooked up chandelier as above. Tested, all lite up fine. Here's the problem.

The switch on the wall(regardless of position, up/down, i.e. on/off)
has a strange interaction with the light. Regardless of the switch position the light comes on(after the initial and subsequesnt throwing of breaker switch for circuit). When the switch is turned to the opposite position, the light goes out(regardless of up/down) AND the circuit breaker is throw. Throwing back the circuit breaker at this point brings the light back on again and it can be turned off with the switch(regardless of position) as per above.

Assuming the original, installed wiring is correct, did I do something wrong in installing the chandelier. I can switch A&B but for a simple light fixture I'm not sure this will fix the problem.

If its not something I did wrong, then what might be wrong with the original wiring? Note bundles of 3 white, 3 reds looks professionally tied/finished in ceiling fixure. There are no shorts that I know of.

Thanks
Tony

 

Classic symptoms of a miswired switch loop. I've already seen this 20 times time week alone.

Are there only two wires in the switch box, no more?

When a switch loop is involved, matching wires by color at the light fixture is always wrong.

BTW, A and B are not interchangeable. Look very closely to see if one of those two wires has a small rib or stripe on it.

Work with us, and we'll get this straightened out.

 

From Tony:

Thanks John. I examined the A&B pair, one has a small (1/16th or less rib). So I'll switch these tomorrow, think that will cure the problem? I always thaought that with a simple lighy fixture it made no diff if you switched pos/neg, but it must make a difference when there's a switch involved, right?

What is a loop swicth, just a simple on/off, right?

"When a switch loop is involved, matching wires by color at the light fixture is always wrong. "

Thanks
Tony

 

No, do not switch the A & B wires. This is not your problem. It is important to get them right for safety reasons, but it is not causing the symptoms you describe. We'll worry about that later. First things first.

Correct polarity always makes a difference to safety. It has nothing to do with a switch.

You do not yet understand a switch loop. Let me briefly describe. There are two basic ways to wire a switched light.[list=1][*]Bring power to the switch first. Insert the switch into the hot connector, and run both the switched hot and the neutral to the light. In this wiring, all black wires are hot and all white wires are neutral.[*]Bring power to the light first. Then run a switch loop to the switch and back. The switch loop consists of two wires, both of which are hot (even if one wire is white). You have at least four wires in the light box, but not all of them connect to the light. If you connect all the wires in the light box to the light, you will have trouble.[/list=1]Please go back to my first post. Find the line that ends with a question mark. Post back with the answer.