NEWBIE:  Fuse keeps blowing in my apartment.  Am I using right fuses? - Page 1
Forum section: electronics / beginners

author: Brooklyn415
author_rank: Newbie
timestamp: January 30, 2015, 08:00:00 pm
content: Hello All,I'm new and I have a question to ask about the fuses in my apt. Not making any repairs, but my superintendent is kind of useless/unavailable so I figure the moreIknow myself, the better, so that I can be prepared and prevent needing to call him as much as possible.I live in a pre-war building. In my apartment unit, there is a small fuse box with 2 sockets to use Amp plug fuses. Apparently, the main fuse box is in the basement of the building and I do not have access to it, only the super does. Whenever a fuse blows, I have to call him (if he answers the phone) and I guess he has to replace the fuse in the main box. When I first moved in, there was a 30A TL type fuse and a 20A TL type fuse screwed into the box in my unit, so of course, these are the fuses I stocked up on. I understand space heaters are "electrically expensive" so to speak; however, I have needed to use one this winter. After blowing the fuse MULTIPLE times, I have since learned that the space heater cannot be used with any other appliances in order to keep the electrical peace. The last time it blew, the super came to ask me if I had a 15A S type fuse because he ran out. I was shocked to hear that he needed 15A because I have at least 50A capacity screwed into my individual unit. I also found out that MY fuses do not actually burn, so I rarely need to change them, it is usually the fuse in the box in the basement. My questions are:1. Can I stock up on and give the super a Cooper Bussmann 15A circuit plug breaker? Is that compatible/easier for him. (i'll keep my own supply as well, just in case)2. I am VERY concerned now about the safety of my circuit. Am I using the WRONG (too many amps) fuses in the box in my apartment unit?3. If the fuse that is burning is the one in the main box in the basement, then what is the box in my individual unit even for? Is it functional? How does it relate to my outlets/ electrical usage?Any help or advice would be greatly appreciated. I've looked up different types of fuses, compatible wire guages, etc., but since I don't have access to the main box, I don't know how much I could find out.Thank you in advance.

author: IanB
author_rank: Super Contributor
timestamp: January 30, 2015, 08:05:24 pm
content: Hi,Usually the downstream fuses (in your apartment) would be lower in value than the upstream fuses (in the basement). This is for two reasons: firstly, so that your apartment fuse should blow first before the main fuse, and secondly because the wires leading to your apartment are likely thinner and have lower capacity than the wires leading to the main fuse box.Fuses are generally sized to protect the wiring that comes after them, to prevent that wire overheating and causing a fire. It seems like the fuses in your apartment are too big. Most circuits in homes are rated for 15 A or 20 A. It is unlikely that you should have more than a 15 A fuse in your apartment fuse box.

author: wraper
author_rank: Unknown
timestamp: January 30, 2015, 09:24:57 pm
content: Isn't there some sign that burned fuses were heating a lot? If the fuse holder have poor contact, it will heat a lot and eventually fuse will burn even if current was not exceeding fuse rating.

author: Brooklyn415
author_rank: Newbie
timestamp: January 30, 2015, 09:44:56 pm
content: To IanB: Thank you for your reply. So then I will get the 15A fuses.Does this mean that if I blow a fuse in the future, it would be my fuse in my unit, and therefore, I can just replace it myself and not have to call on the super? I would probably have to do this carefully, if this means that the main circuit will still be connected as I'm screwing in a new fuse.To wraper: I am not sure if there are any signs around the main fuse, the one that keeps burning, because I do not have access to that. There does not appear to be anything ominous looking in my apt though. Even if there was something, I doubt my super would let me know, if he even knows what to look for himself (ugh).Can I use the mini breakers for any OR all of these fuses?Thank you guys.

author: katzohki
author_rank: Frequent Contributor
timestamp: January 30, 2015, 11:00:36 pm
content: Yikes! Is this in the US? I would get the opinion of a certified electrician (hopefully someone you can call and ask what he thinks) and then maybe contact the actual building owner. I'm concerned about the safety of this situation and whether things are even up to code.In the meantime, see if you can figure out what your heater is rated at.

author: devanno
author_rank: Regular Contributor
timestamp: January 31, 2015, 06:51:16 am
content: If the wall outlets associated with that 20A or even 30A fuse are standard 15A wall outlets, then you should only be fusing for 15A. From the fuse to the endpoint connector, all components must be able to handle the total rated current. I doubt you have 30A wall outlets... rare in 110/120V applications at best, especially residential. If memory serves (I'm not an electrician), 30A requires 10AWG wire... 20A requires 10AWG, and "normal" 15A circuit wiring is 14AWG.I'm not suggesting that you open the boxes to check. But if these are indeed over-rating the capability of your building, in-wall fires can be the result... and the indication that the main panel (sub-panel feed) is blowing is certainly an indication of a problem. If this has been done in your apartment, there is the possibility that others have done similar things, which would create a significant fire and safety hazard. Someone else suggested contacting the building owner... I would second that suggestion.