Electrical Question

Parent Cafe
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<p>I feel a little stupid, but I can’t figure this out. Tried a quick web search, but I think I am not well enough versed in this topic to decipher what I found.</p>

<p>I have a moisture problem behind some tiles in a shower in my house. My insurance agent & builder recommended that I run a small dehumidifier in the shower for a couple of months to help it dry out, then have it regrouted (whether there is mold back there and whether it should be completely retiled is a whole different discussion, don’t want to go there in this thread…).</p>

<p>I moved the small dehumidifier that I have into the shower, and went to plug it in. The “test” button on the outlet keeps popping out when I turn the dehumidifier on. I was able to use the dehumidifier in my basement in the past, no problem (but it was in the room with the furnace, air exchanger, etc., so that room may be wired differently). The outlet works fine for other stuff (eg, charged my cell phone there this morning after trying the dehumidifier, and it worked fine). It is a 3 pronged plug, if that makes any difference.</p>

<p>Is there something I am missing? Are some outlets only good for a certain amp amount or something like that, and my dehumidifier requires something more? Will I have to have an electrician come in to get this dehumidifier working? :confused:</p>

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<p>The test button on the GFCI outlet will “pop” in the presence of moisture, to prevent a life threatening electrocution hazard. To the best of my knowledge (I’m not a licensed electrician), the test button on a GFCI does not operate as a circuit breaker or fuse to prevent an overload, so I doubt that the amp draw on the dehumidifier is “too much” for the outlet. Most residential circuits are typically 15 or 20 amp rated, which means that a current draw higher than the rating will “pop” the circuit breaker or fuse at the service panel for that circuit. If the breaker “pops” at the service panel, then the draw of the dehumidifier (particularly at startup or when the compressor kicks on as that’s when the amp draw is highest) might be too much for that circuit, contingent on what the breaker amp is and the amount of other “stuff” in use on that feed.</p>

<p>I don’t think that’s your problem.</p>

<p>You said “I moved the small dehumidifier that I have into the shower…”. Did you place the unit physically within the stall? You might have gotten any or all of the three prongs on the plug wet (or even damp). Enough moisture on the plug will trigger the GFCI when you plug it in. Try drying off the plug on the dehumidifier with a towel and a blow dryer for a minute or two. </p>

<p>I would NOT recommend running any appliance within the confines of a damp/wet area like a shower, particularly if there is residual moisture on the floor & walls. If it’s a shower that you’re currently not using because of the water issue behind the tiles, I’d say ok, but I would still urge extreme caution mixing electricity and water. </p>

<p>Safety is the key here.</p>

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<p>Agree with violadad. Be careful. I’m surprised that a builder would recommend running a dehumidifer and not pulling out the tile and making sure the problem is taken care of properly.</p>

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<p>GFCI outlets are tempermental sometimes. Assuming you don’t have the unit sitting where it is wet, It may simply be drawing too much current through the GFCI outlet. If you want an alternative, try purchasing a HEAVY DUTY (high amperage) three conductor extension cord that will reach to a different outlet outside the bathroom. That should work. Keep in mind that you are defeating the purpose of the code requirement for GFCI outlets in bathrooms when you do it that way. Make sure the de-humidifier doesn’t have some wiring flaw.</p>

<p>The GFCI principal (ground fault circuit interupter) is that situations might occur where a “ground fault” occurs. An example of a ground fault is a person coming in contact with the electrical circuit, and shorting that circuit to “ground” (Ie touching a water pipe or fixture while in contact with the electricity). This might not draw enough current to trip the circuit breaker at the breaker box, but with a GFCI in the circuit, the unequal current flowing in the ac lines in this situation is detected, and the GFCI trips, even if the different in current is quite small. The idea is to make sure that “leak to ground” isn’t going through a person. [The circuit breakers in the house are there to protect the wiring from melting in short circuit situations, and to prevent fire from starting from the same situation. They are not there to protect people from being electrocute…and they don’t.]</p>

<p>You could test your dehumidifier on another GFCI circuit, such as in the kitchen, and see if you get the same behaviour. Its quite possible that the bathroom GFCI is not operating correctly.</p>

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<p>I can’t help you with the electrical problem, but the idea of using a dehumidifier to fix a moisture problem behind tile seems really dumb to me.</p>

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<p>Yeah, mathmom, it does sound really dumb. But there is a reason… Lol, ebeeeee, my builder has ZERO interest in actually fixing the problem with this shower. </p>

<p>My house was built 8 years ago. Shower leaked into the room below the first year, builder’s tile guy finally (after 18 months of dragging his feet!) fixed it by retiling the whole shower floor. Significant cracks appeared in the grout in the floor 28 months ago (long, wide cracks); builder’s tile guy came out with builder and a 2nd opinion tile guy. They agreed on a plan to fix it, but the tile guy did not actually carry out that plan (he did a lesser patch). I probably should have sued then, but didn’t… Now (1) the two year statute on suing over that fix just expired (conveniently right before this moisture was detected), and (2) the tile to replace the whole shower (and it is big, master bath shower) is no longer available.</p>

<p>I had the builder and a mold guy from our insurance company out last week to look at a separate mold issue (not related to this). I asked the mold guy to measure moisture behind the tile in shower (which I have not used in several months, as it is a pain to clean and only D2 and I live in our house now). He said moisture behind the north wall of the shower is 100% (!), and there are some gaps in the grout on that wall (as well as a new crack in the floor). He and the builder said, “run a dehumidifier in here for a couple of months, then regrout the shower”.</p>

<p>I think it is that or tear out the whole shower and start over (with new tile). I can’t afford to tear out right now (this is a big shower with some matching tile outside it, you could shower a cow in it, I figure we are looking at ~$4,000 to redo the whole thing). So I thought it would be low cost to run the dehumidifier and check the moisture again later (meanwhile continuing to search for the current tile). I am pretty sure I can’t sue under our state laws (although if I pay for tearing out and replacing, I will be carefully examining and photographing the previous construction at every step just in case I can). And I have talked to my attorney.</p>

<p>Oh, and the insurance company won’t cover the other (unrelated) mold damage, either. One more reason I can’t afford to tear out the shower right now, as that is a higher priority.</p>

<p>Just to alleviate everyone’s concerns (thank you for them), the shower floor is bone dry, and I positioned the drain of the dehumifier right over the shower drain. And I don’t intend to turn the shower on any time soon.</p>

<p>dadx, I did get a heavy duty high amperage extension cord (needed on just to reach the bathroom socket), I took the dehumidifier instruction book to the hardware store and had the guy there help me pick one out. But it won’t reach outside the bathroom. I think I need to move the dehumidifier and try this with another outlet, maybe even back to the one in the basement it was used with previously.</p>

<p>Thanks for the advice, let me know if you think of anything else. I will update when I have tried it in other locations, too.</p>

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<p>The button on the GFCI outlet in our bathroom would pop when we used our hair dryer. I cleaned out the lint that accumulates at the bad end of the hair dryer and now I have no trouble. So I agree, those outlets can be persnickety.</p>

<p>Also agree that running a dehumidifier for MONTHS to dry out a shower seems really off…</p>

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<p>What’s underneath the tile? If it’s “green board”, it maintains its strength even when wet, and drying it out makes sense, but “months” does seem long.</p>

<p>Can you get to the OTHER side of the tile somehow? From underneath? Or from the wall on the other side? It would make sense to me to dry out the backing–whatever it is–as fast as possible, especially if you already have mold problems. It might even be worth it to pop one tile–very carefully–so that you can make a hole in the backing board so you can dry things out properly.</p>

<p>And take a look for the tile on EBay, you’d be amazed.</p>

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<p>I am not sure what is on the other side of the tile. It is on an outside wall on the 2nd story (in fact, more like 3rd story, as it is on the walkout end of the house), so there is no way to get to it except through the tile itself. I am not going to try to take out any tile myself - - I will get a professional in to do it if it needs to be done. </p>

<p>I’ve been searching for the tile on eBay and other online sources (and plan to call the tile store this week, they may know some sources I don’t).</p>

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<p>I think I got the original problem with the dehumidifier figured out. Both plugs in the bathroom are right above the sink (and both pop the test button out when I try the dehumidifier, but other smaller appliances work in them). Ex-H suggested that maybe the builder lowered the amps in those outlets in case someone dropped their hairdryer or electic shaver in the sink. Sure enough, plugs in the bedroom outside the bathroom run it just fine. So the answer is a longer extension cord to reach outside the bathroom. Doesn’t help me find my tile and solve the shower issue long term :slight_smile: But it solves the electrical question, I think.</p>

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<p>Soo… I finally got around to getting a longer cord and plugging in the dehumidifier. I bought a 50 foot outdoor cord rated the same as the indoor cord I had tested with (the indoor cords didn’t come any longer than the 12 footer I had purchased before). I had someone at the hardware store help me pick it.</p>

<p>When I plug the dehumidifier in with the new extension cord, it runs. BUT, every minute or so the dehumidifier makes a sort of popping sound, and the lights flicker in the bedroom where it is plugged in. I unplugged it after realizing it was doing this (although it ran for a while, maybe 20 minutes, as I plugged it in and walked out as soon as I was sure it was running…).</p>

<p>So now I am not sure what to do. This seems dangerous… Anyone have any thoughts? I am planning to move the dehumidifier back across the room and try again with the shorter cord just to see if this occurs. Sigh…</p>

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<p>Sounds like it could be a either a voltage issue with the longer cord, or maybe a compressor issue with the dehumidifier. Any unit like a compressor will require a short term heavy amp draw when the compressor cycles on and off. Did it “pop” and the lights licker in the basement? Are two circuits the of the same amperage? Is the compressor short cycling?</p>

<p>Longer power cord runs require heavier wire based on the “load” of machinery requiring power. Google “extension cord sizing” or similar wording and a number of explanations and sizing charts will come up. The guy at the hardware store should have steered you correctly, but thhat is not always the case.</p>

<p>Again, I repeat my earlier caveat, that if it seems unsafe or not right, it probably is. Proceed with caution if you have no diagnostic talent or skill.</p>

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<p>I think you should just forget the humidifier thing in the first place - I can’t imagine that it’ll help with the problem.</p>

<p>If you still want to use it, keep in mind that some heavy current dray electrical items specifically state to not us an extension cord long than ‘x’ with ‘x’ usually being less than 50 feet. There’s a loss in the electrical cord which can drop the voltage at the appliance and possibly cause it to work harder and draw more current (i.e. to keep the same power draw the current must go up if the voltage goes down - Power = current x voltage).</p>

<p>You could try it with a humidifier that consumes less power but really you should figure out another way to solve the problem. A key to it is to understand why you have the moisture problem there in the first place - i.e. a one time leak or something more pervasive.</p>

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<p>In the short term, could you just set a fan on the floor of the shower and run it 24/7?</p>

<p>We must have had the same builder! Ours thought he was doing us a favor by running the electrical floor heat UNDER the shower - not to wise… Make sure when you get your new tile that they use caulk instead of grout where vertical meets horizontal. </p>

<p>My SIL just went through a whole house redo because of mold behind their stucco. Their house was built air tight in the early 90’s before air exchangers.</p>

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<p>uscd<em>ucla</em>dad, as I think I might have mentioned above, it would cost thousands of dollars to replace this shower because it is very large, the tile is not available, and the tile sort of goes around a corner and into an area outside the shower that would also need to be retiled to make it look right. I am past the point in time where my builder can be held responsible in my state. There are visable cracks in the grout (whether there should be is a different discussion, but they are there). As soon as they start taking tile out to explore behind it, I have a problem, as I have almost no replacement tiles left and they are likely to break some. Then I will surely have to pay the big $$ to redo the whole shower.</p>

<p>So as far as I can see, my options are to do as the builder & mold guy & insurance guy recommended (work to dry the area out as much as possible, then have it regrouted), or pony up about $10,000 for a replacement. Wanna help with tuition payments this year so I can cover that? :)</p>

<p>But I do think you may be right about the length of the cord. I am going to try the shorter cord (when I get back from Turkey Day traveling, trying to get out the door tomorrow…) and see if the problem is still there. If not, maybe two 12 foot cords together might do the trick. But if you want a hot stock tip, buy into Menards… they are selling a lot of electrical cords lately.</p>

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<p>I agree with UCSD<em>UCLA</em>Dad (and others) who think using running the dehumidifier is roughly the same as “take two aspirin and call me in eighteen months.” Humidity behind the tile will not be fixed by drying the shower enclosure (in my experience).</p>

<p>BTW, cracks in the floor tile are obviously not a compliment to the original builder either. A tiled bathroom floor should last decades … even if water regularly splashes onto it.</p>

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<p>On the tuition payments - I’m already obliged on those so I guess I won’t be able to help you on that. :wink: </p>

<p>So I guess they figure this problem is from cracked grout that allows the moisture to get into the wall? Have you quit running water in that shower until you can get it dried out? If not and it’s therefore not drying out, then is that a possibility? If not then I don’t see how it would ever dry out (unless you moved the shower here where it hasn’t rained in 6 months and will be in the 80s and dry this week). If you do use that shower still I hope you have a good evacuation fan to such the moisture out but even some of those aren’t placed that well for the moisture evacuation or some just evacuate it to the attic.</p>

<p>If it’s a really small area like a few tiles have you discussed the idea of just using a regular blow drier to dry out that area? And if not that then maybe a room fan blowing constantly across it for some number of days might help and maybe it’ll draw less current. </p>

<p>What’s the power rating of your dehumidifier (‘watts’)? Can you get a dehumidifier with a lower rating?</p>

<p>One more thing I’m sure you’ve already thought of - if the shower wall you’re concerned about is an inside wall as opposed to an exterior wall of the house, can you access it from the other side to get at the inside of the wall? i.e. just cut a foot square piece of wallboard out from the other room to get at drying the wall. It’s pretty easy to repair an opening in the wallboard like this.</p>

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<p>edad, I am not using this shower at all right now (have run it once in the past few months to wash down some drain opener). A humidity measuring device placed in the shower right by the wall with the problem (an outside wall, so can’t get at from the other side) is measuring 50-55% (I have been watching it for a few days, it is steadily in that range).</p>

<p>So I am still having trouble with this dratted dehumidifier. I moved it out into the bedroom and plugged it straight into the wall (yes, 3 pronged plug on the dehumidifier and the wall plug is 3 pronged as well) just to see if the snapping problem would go away. It is still making that snapping noise every 30 seconds or so, even with no extension cords. And the lights still flicker… I tried to call GE, but without a paid service contract (which I don’t have), I can’t seem to reach a person. Searched the internet for info - - the model before this one (one letter off) was recalled for an electrical problem, but no info like that on this model. It is several years old, so I assume it would have been recalled by now if the problem was common.</p>

<p>I was reading the service manual, and it says, “The dehumidifier should always be plugged into its own individual electrical outlet which has a voltage rating that matches the rating plate.”. How can I know the voltage rating of my outlet? And what is the “rating plate”? Any info from you electrical types would be appreciated!</p>

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<p>I’m sure the voltage ratings are okay since there’s a single standard for the USA - 120volts ac. There may be some indicator on the dehumidifier around where the cord attaches stating the input voltage and possibly the input current. Placing a higher current draw device at the end of a long extension cord can drop the voltage at the unit though which might cause it to draw excessive current to operate which could be a problem but you eliminated the extension cord and apparently still have a problem.</p>

<p>I’d be concerned about this ‘popping noise’ and flickering lights although if your unit has a compressor, like an A/C unit, that can cause the lights to dim for a second or so while it starts up.</p>

<p>Can you try a different unit?</p>

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<p>Only if I buy a new one :(</p>