ECN Electrical Forum - Discussion Forums for Electricians, Inspectors and Related Professionals

Topic Options
Rate This Topic
#187496 - 06/28/09 08:29 PM Which Cartridge Fuse?
thiggy Offline
Member
Registered: 05/12/04
Posts: 24
Loc: B'ham Al
I have an old family farm house with a 125 amp Square D breaker box. The service disconnect is a 100 amp Square D cartridge fuse. I have never had the main blow, but I decided that I better have a spare pair of fuses on hand just in case, as in this rural area it would be difficult to locate one in a hurry. I drove to the nearest city and located fuses at Lowes, but I am not sure which one of the two types they had should be used for my application. The heavy-duty time-delay one said it is "for motor and main panel protection. (FRN-R)" It indicated that "for lighting or electric heating circuits use general purpose fuses.(NON)" I use window AC units for cooling, and 1500 watt portable heaters for infrequent use in winter heating. Water heaters are also electric. (This is generally just a week-end house.) Which type of fuse would be the most appropriate for my use?
Top
Work Gear for Electricians and the Trades
#187497 - 06/28/09 10:41 PM Re: Which Cartridge Fuse? [Re: thiggy]
gfretwell Offline


Member
Registered: 07/20/04
Posts: 9039
Loc: Estero,Fl,usa
I would go with the FRN.
That will tolerate a short time spike in current.
The biggest opportunity for a spike in current is when you have a power glitch and the service would see locked rotor from every motor that was running at that time.
_________________________
Greg Fretwell
Top
#187499 - 06/29/09 01:28 AM Re: Which Cartridge Fuse? [Re: gfretwell]
Trumpy Offline


Member
Registered: 07/05/02
Posts: 8211
Loc: SI,New Zealand
Yeah,
I agree with Greg.
You really need something with a bit of time delay on it for a main fuse.
After all, the fuse/CB that is electrically closest to the fault (ie, a sub-circuit fuse/CB) should operate first, in any electrical system.
Anything less is poor design.
_________________________
Let's face it, these days if you're not young, you're old - Red Green grin
Top
#187503 - 06/29/09 09:19 AM Re: Which Cartridge Fuse? [Re: Trumpy]
electure Offline


Member
Registered: 12/24/00
Posts: 4259
Loc: Fullerton, CA USA
You answered your own question.

Quote:
The heavy-duty time-delay one said it is "for motor and main panel protection. (FRN-R)"
Top
#187509 - 06/29/09 10:09 AM Re: Which Cartridge Fuse? [Re: Trumpy]
thiggy Offline
Member
Registered: 05/12/04
Posts: 24
Loc: B'ham Al
Thanks for the responses. I shall go with the time delay fuse. (I actually bought two of both types with the intention of returning one pair after I determined which type I should use.)
Top
#187517 - 06/29/09 05:24 PM Re: Which Cartridge Fuse? [Re: thiggy]
JBD Offline
Member
Registered: 07/12/01
Posts: 599
Loc: WI, USA
There is almost no reason to ever install an NON fuse. For all intents NONs are old technology, and are almost always sold based on price only.
Top
#187526 - 06/29/09 08:36 PM Re: Which Cartridge Fuse? [Re: JBD]
gfretwell Offline


Member
Registered: 07/20/04
Posts: 9039
Loc: Estero,Fl,usa
We used NONs to protect electronics and there was even a faster blowing fuse that we used for the input to switcher power supplies way back when they were a big cabinet full very expensive parts.
_________________________
Greg Fretwell
Top

Member Spotlight
Member Since: 11/17/00
Posts: 2232
New in the Gallery:
SE cable question
Featured:

2017 NEC and Related
2017 NEC
Now Available!

Shout Box


Who's Online
1 registered (ghost307), 67 Guests and 11 Spiders online.
Key: Admin, Global Mod, Mod
 
New in the Gallery:
SE cable question
 
Top Posters (30 Days)
Admin 49
HotLine1 43
gfretwell 18
Ruben Rocha 12
Trumpy 9
 
Newest Members
Freecrowder, clee512, Jdscott2005, FAIZAN, Regitest2

ECN Electrical Forums - sponsored by Electrical Contractor Network - Electrical and Code Related Discussion for Electrical Contractors, Electricians, Inspectors, Instructors, Engineers and other related Professionals