Fuse question

nick-caper · Post by **nick-caper** » Thu Mar 06, 2008 9:54 am

This question has caused arguments at work.

I have 120 amps going to a device. Can I use 2 60 amp fuses in parallel to let that 120 amps pass through or even 3 40 amp fuses in parallel?

Many say no but I say only in parallel cause I see amps using many fuses this way instead of useing one large fuse.

Post by **fuzzysnuggleduck** » Thu Mar 06, 2008 9:58 am

Yes, it will work.

However, when one fuse blows, the other will blow right away afterwards.

Post by **Bfowler** » Thu Mar 06, 2008 10:00 am

i would say yes. in fact, many fuesblocks use that pricipal.

what is thier argument for no?

i know i am using 2 60 amp fueses in parallel off of my PG 902k battery terminal right now (and have been for almost 2 years)

Post by **Francious70** » Thu Mar 06, 2008 10:17 am

Yes, adding them in parallel should "theoretically" add their values.

nick-caper · Post by **nick-caper** » Thu Mar 06, 2008 6:52 pm

Well. Here is the story.
I been building computers for the worlds largest family owned oil field company. This company pays engineers to come up with the best circuit boards and best parts to use. Well there are 2 particular engineers that I been working with and they both couldnt get there prorotype computer to work for 2 years. Here I come, a so called novice at there field and get the computer running. Not only that but I help them finish building it!
So a year passes and I notice one of the circuit boards has a useless fuse on it. Actually this is the same circuit board that was built wrong by the engineer that couldnt get the computer to turn on! Anyway. The situation is that We built an inline fuse holder with fuse installed on a long cable that is attached to a very important piece of gear. If this gear isnt properly connected it could cost the company thousands per day! So we have an inline fuse of lets say 10 amps (not the real value) which is sufficient. But then I noticed there is also a small 12 amp fuse on the circuit board that is connect to this cable and gear. So basically there are 2 fuses connected to this gear in parallel that is putting the specs of the gear way off. We want to make sure that fuse pops at 10 amps not 23 amps! So I show the engineer and his fellow co-workers and also my co-workers and boss. The engineers laugh and say Im seriously in need of vacation. My boss looks at me an djust walks off as if I am a retard. This was the same way they reacted when I told them how to make the computer run. So now what I will do is make a test stand and show them my theory is correct and ask for a raise!

Thanks

Post by **Bfowler** » Fri Mar 07, 2008 9:07 am

so they are in parallel but later down the circuit?

i'm not much of a gambaler...so its hard for me to say "test it" with super expensive equipment..even when i'm 98% sure

can you draw a ms paint diagram of the fuse layout?

nick-caper · Post by **nick-caper** » Fri Mar 07, 2008 10:04 am

No we will test it on a simple power supply....

Post by **Bfowler** » Fri Mar 07, 2008 10:35 am

ah....well in that case...rock his world!