A while back I posted about a basement room I was adding. Going well, thanks for asking.
Tonight I finally got to installing the 240v baseboard I bought back in November (I said it was going well, not going quickly). I had run the circuit and installed the t-stat a few weeks ago, before sheetrocking. Anyway, when I wired it up- nothing. I have 2x120 at the wires, so I know that’s good, and the t-stat is working becuase it turns the juice on and off (I put my meter on the wires and had someone adjust the t-stat). So the problem is not in the supply.
I checked all the connections three times, so I am confident that’s not the problem. It’s a pretty simple 3-wire connection (2 hot and one ground). Since I bought this so long ago, I don’t want to drag it back to HD for a return fight without being certain it is bad. Is there some continuity or resistance I can check? The ground wire on the unit is secure.
As a bonus question, what’s with this stuff that is 240v that uses the ground as a return? I thought that was considered not good these days? In fact, I thought code was prohibiting that. As you may know from a previous thread, I had a recent experience with a new 240v cooktop that was designed for 3-wire installation.
You can do a continuity check, disconnect power and check between hot A and B also check between Ground and A and B. I can only assume that this is an electric heater unit. If it is you might want to make sure the element or elements are in their sockets. I am not sure if this unit is up to code because it lacks a neutral but there should be no problem as the hots are out of phase with each other. Good luck let us know
You say you have 2x120. Is that testing each of the hots to ground? Test the voltage between each of the hots. It should be 240 VAC. Also the power should come from a two pole breaker. What type of stat do you have. If the stat is wired up direct it needs rated at 240 VAC.
Yes, I meant that each hot is 120 to ground, so I didn’t look at the hots to each other. I will check that tonight.
I followed up and I do have continuity (on the baseboard) between the grounds, as well as between the heating element leads (meaning I set the meter to read ohms and I get effectively no resistance).
The power does indeed come from a two pole breaker. The stat is a two pole line voltage stat, rated for 240VAC.
The unit is a Marley Fahrenheat 1500W, and it has no t-stat of its own. You must purchase one separately, either one that plugs into the end of the baseboard or a remote wall-mount unit. I went with the latter. So I have a 30A 2-pole breaker* feeding 12-3 to the t-stat in the wall, both hots run through the stat with the ground and return continuing through the box, and on to the baseboard.
The t-stat is also made by Marley and specifically what they suggest for use with the baseboard, although I would think any line voltage two pole unit would work.
*I know the 30A breaker is too big for the 12-3; it was there and I will be changing the breaker to a 20A, but I was just making sure that everything works first. I have to go into the panel to finish the room wiring, and I will do all that work at one time.
If you accidentally grabbed both wires from the same leg, the voltage across the two wires will be 0.
I assume you used a double circuit breaker so, in the box, the two wires are right above and below each other.
ETA, I just read the rest of your post and it appears you did use a DPDT breaker, so you should be fine there.
There are some pannels that the the breakers that are side by side are the same phase. That is 1&3 are phase A, 5&7 are phase B, then 9&11 are again phase A. so do check the voltage between both lines.
Thanks again for all the ideas. I will try wiring directly, and I will check the voltage across the two hots. All the 240 circuits in my panels (there are 5) are top-bottom (1&3, 6&8, etc) and all work fine including the 50A that I installed recently for the new cooktop, and while I don’t know what they read across the the hots, the connected devides work fine. That includes range, cooktop, well pump, etc.
Of course, it is possible that all this is just to confirm a non-functioning unit, but for something as simple as a resistive heater that is surprising.
Plus, even if I were only getting one phase, I should still get some heat from the baseboard, right? It is stone cold even after 20 minutes.
But this is a really helpful discussion- thanks for the ideas and helping a non-electrician out. More guts than brains, that’s my motto.
I’ve a single pole thermostat on a 240v baseboard heater, and the documentation points out that there is still voltage present when the thermostat is off.
[QUOTE=OldOlds;
Plus, even if I were only getting one phase, I should still get some heat from the baseboard, right? It is stone cold even after 20 minutes.
But this is a really helpful discussion- thanks for the ideas and helping a non-electrician out. More guts than brains, that’s my motto.[/QUOTE]
No. The current flow is from one hot line to the other line. If there is only one hot leg or they are the same then there is no current flow. The ground is for safety and should not have any current flow.
Please disregard my previous misinformation. I went back at it with the multimeter last night, and now I am getting 120 to ground on one of the hots, and only 20VAC to ground (or neutral) on the other. Between the hots I get 50VAC. This is both at the t-stat and at the heater! I don’t know if I mis-read the meter before, or if possibly I read the same hot twice- whatever I did it was clearly a bonehead move on my part, not reading it right.
Since this is a basement, I can see the straight run from the t-stat’s box back to the panel, and there are no other connections or visible damage to the wire. But this makes me think there is something wrong in the panel, either with the breaker or one of the connections- although I am open to other ideas.
History of the Circuit:
This was an existing 220V/30A outlet that was not in use, as it was for an electric dryer the previous owner had, but I converted to gas. So I shut the circuit off over 10 years ago and didn’t think much about it. When I began the basement project, I realized that I had a 220v circuit available, so I pulled the wire from this circuit and re-routed it to supply the heater. I thought I was being ecenomical. As I mentioned upthread, it was a 30A circuit and I needed to replace the breaker with a 20A, which I planned to do when I install the circuit for the room wiring.
Am I correct in assuming that if the wiring is a straight, uninterrupted run from the panel, locically I must have a problem in the panel? All other voltages in the house are fine, from both legs in the panel. The panel is well balanced.
Assuming that the wire is uninterrupted isn’t good. Defects in even brand new wire are possible. Defects in re-used wire are not just possible, but likely.
If it were me then I’d check the wire you used to go from the panel to the heater for continuity. It would suck if something you used to hang the wire (a staple, clamp, whatever) had damaged the wire. Most people’s meters don’t have leads long enough to do this - what I’d do is connect a wire (long enough to go from the panel to the heater) via wire-nut to the end of the wire in the panel (after removing it from the breaker of course) and then carry the loose end of my jumper wire down to the heater. I can then check the entire length of that wire even if it’s stuck behind a wall, or routed in some impossible to visually inspect location.
Odds are you’ve got issues in the panel, but it can’t hurt to be thorough. Doing this will let you know 100% where the issue is. Your logic is sound; if the wires all have flawless continuity, then your issue is in the panel, likely with the mounting of the breaker to the panel itself (you said you replaced it with a different sized one?). If the wires do not have good continuity, there may be some kind of break in the wire or a bad connection hidden away behind the wall somewhere.
And no, I didn’t replace the breaker yet- it’s on the to-do list. The new circuit includes 12 gage wire, and the heater only draws ~7amps, so I will be downgrading the breaker to a 20A.
disconnect the heater/thermostat from the wires and measure the voltage across the two hot wires at the point they would connect to the heater/thermostat. you want it to be 220V.
if it is not, then measure the voltage at the wire connection points on the circuit breaker. you want it to be 220V.
if you don’t have 220V at the heater end of the wire but do have 220V at the circuit breaker then your wiring or its connections are bad.
there is a problem with methods and safety here. inside the circuit breaker box are many opportunities to come in contact with lethal amounts of electricity (when working there you should be standing on a dry piece of wood is a minimal precaution, measurements should be made with only one hand).
there is a problem with an inexperienced person with their terminology and measurement procedure. also doing the procedures in a safe manner can be a problem, what looks good to an inexperienced eye may not be a correct procedure which could fail immediately or likely fail at a later time. failures are a risk to life and property.
a cable, breaker or heater might need to be replaced. connections might need to be cleaned and remade. you might need to work inside the circuit breaker box, a dangerous location.
I will be repeaing much that has been said.
Disclaimer: Working in a electrical panel can be dangerous. Fallow safety procedures. in the paneluse only onehand keeping the other hand in pocketor behind the back. Look to make sure that you can not be grounded anywhere. Standing on a board is a good idea.
Start at the breaker. Check the voltage at the breaker load connections. Phase to phase and phase to ground. If you get good readings go to first junction and do the same. And so on until you locate between which two pooints you are loosing voltage. Turn the breaker off and check with volt meter to besure it is off. A simple test with out gettting a lenght of wire is to disconnect both ends of the wire in question. Test everything for voltage. Then ononeend connect all three wires together, both hots and the ground. Go to the other end and check for continunity between each hot and ground and hot to hot. If you end up with no continunity on one wire the replace the section. If all three show continunity then you had a bad connection.
I have done work in the panel before, and I am generally pretty comfortable in there. Rubber soled shoes, thick dry board, and one-hand are the rules. I have to replace the breaker anyway (can’t have 30A with 12ga wire), so maybe I should start by shutting down the panel, putting in the new 20A breaker, and seeing if I am back at 120 at the junction box- seems like the safest first step without costing any extra work. If that doesn’t do it, then the only other possibility is that the wire from the panel to the junction box is bad (assuming that both legs in the panel are 120, which I know since all the other circuits are OK).
What surprises me most is this: I would think that if you have low voltage, it would necessitate increased resistance, which in turn means heat. That is, I did not know a condition like this where voltage is low could exist without ultimately causing a fire.
I also learned something in this thread, which is that devices can produce energy (heat) across the two hots. While I understand the concept of potential difference, I thought household wiring always flowed from the hot to the neutral/ground.