Load cdr acting like a neutral cdr

[torint]

I went on a svc call today, I have seen this problem before but I can't figure out why this is happening. Customer complains that bedroom is not working. Found a j-box that had cdrs apart. I put my volt tester across cdr #1 and cdr #2 and read 120 volts. Cdr #1 was hot and cdr #2 acted like a neutral. Now one never wants to tie a hot and neutral together but I knew that these two cdrs were initially tied together and had come apart. I put them back together and the problem was solved. My question is: Why did cdr #2 (load) act like a neutral? I expected it to be "dead" and I did'nt expect to find any voltage across the two.

 

[iwire]

Re: Load cdr acting like a neutral cdr

There most likely was a load down line turned on plugged in etc.

If you had a load down line when you put the meter between the two conductors the meter completed the circuit and was now in series with any loads.

Once this happens the meter will read the voltage of the circuit.

With the power off and a meter set to Ohms touch the leads of the meter to one of the conductors and neutral.

A very low resistance (almost 0) would indicate a short, a medium to high resistance would indicate a load down line.

 

[torint]

Re: Load cdr acting like a neutral cdr

I thought that but if you have a regular sgl pole snap switch and you take the switch out of the ckt, and then do the same check you don't get that kind of reaction.

 

[iwire]

Re: Load cdr acting like a neutral cdr

I sure wish I could draw diagrams like Ed does.

Really you should get the same reaction by replacing a single pole switch with your meter.

This should read the voltage of the circuit, I do not have any good answers as to why you did not find this to be the case.

This is a good way to check for a bad cartridge fuse.

You put your meter leads on each end of the fuse if it reads 0 to 1 or 2 volts you have a good fuse, if it is a bad fuse you will read the circuit voltage as the meter completes the circuit.

 

[hurk27]

Re: Load cdr acting like a neutral cdr

If you turn a single pole switch off you will have 120 volts accross it. the load will be the connecting wire to the neutral. think of it this way any time you have a load in a circuit and you have a break in the circuit there will be (depending on the circuit) 120 volts ,240 volts or 277 volts accross the break. this is because the load is of a low enough resistance that it will conduct the neutral return path through it.
Have you never recived a shock from a switch? it's because you got inbetween the hot and the load which by the way is still connected to the neutral.
Here's and example that through's quiet a few electricans. you have a house that is fed through two 60 amp fusses one of them blows but you still have 120 volts on both legs and everything still works except the drier no longer heats up and the electric hot water heater doesn't heat up why is this. and I have seen many run out and change the heating element in both before they find the problem. the problem is the 240 volt heating element is conducting the A phase to the B phase resulting in both legs still being hot but there is no 240 volts because B phase is now A phase through the heating element.

 

[electricman2]

Re: Load cdr acting like a neutral cdr

This illustrates why it is never safe to assume that a neutral conductor is safe to touch. If it is broken somewhere between where you are and the panel and there is a connected load, it will have line voltage on it! Treat every wire as if it were hot.

 

[hurk27]

Re: Load cdr acting like a neutral cdr

A good rule to live by littarly

 

[a.wayne3@verizon.net]

Re: Load cdr acting like a neutral cdr

Yes it is good advice,especially if the circuit has a flourescent ballast load on it...Open neutrals are dangerous,who here has used an Ideal plug tester and has read hot ground reversed when plugged into a circuit with an open neutral???