ECN Electrical Forum - Discussion Forums for Electricians, Inspectors and Related Professionals
ECN Shout Chat
Shout Box
Recent Posts
Fujifilm Recalls Power Adapter Wall Plugs
by Admin. 01/16/18 07:04 PM
VDE 0100 to introduce AFCIs
by sparky. 01/16/18 06:36 PM
Air Compressor feeder conductor sizing
by Potseal. 01/15/18 09:08 PM
Under carpet cable?
by HotLine1. 01/15/18 09:57 AM
New in the Gallery:
Housebilding DIY wiring
SE cable question
Who's Online Now
0 registered members (), 19 guests, and 7 spiders.
Key: Admin, Global Mod, Mod
Previous Thread
Next Thread
Print Thread
Rate Thread
Standard Fuses #8919
04/09/02 10:17 PM
04/09/02 10:17 PM
R
Randy Barnett  Offline OP
Junior Member
Joined: Apr 2002
Posts: 4
Loveland CO
HI Dan,
Thanks for being here!
240.6 on Standard Ampere Ratings for fuses and fixed-trip cb's is pretty well self-explanatory. But, why a fuse with a standard ampere rating of 601 Amps? Is this a special application of some type?
Thanks in advance!

Work Gear for Electricians and the Trades
Re: Standard Fuses #8920
04/10/02 08:37 AM
04/10/02 08:37 AM
sparky66wv  Offline
Member
Joined: Nov 2000
Posts: 2,236
West Virginia
Great Q!

I always thought that was a typo... and how could they possibly tell the difference between a 600 and a 601? (Put >601A on it and the 601 will open first?)


-Virgil
Residential/Commercial Inspector
5 Star Inspections
Member IAEI
Re: Standard Fuses #8921
04/12/02 11:34 AM
04/12/02 11:34 AM
D
Dan Neeser  Offline
Member
Joined: Mar 2002
Posts: 29
St. Louis, MO, USA
Randy,

That is probably one of the most asked questions when it comes to fuses. In fact I had the same question last week.

The reason there is a 601 fuse is to give flexibility. Class R and J fuses only go up to 600A. Above 600A, a Class L fuse must be used. Class L fuses range from 601A-6000A. The first case size of a listed Class L fuse is 800A with fuses sizes typically of 601, 650, 700, 750 and 800A.

Thus, if you have a circuit that could be sized at 600A, but may have to be increased in the future due to future expansion or motor inrush issues, Class L is the obvious choice. By going with a 601A Class L fuse, in an 800A disconnect, the fuses could be increased in the future up to 800A, provided conductors with an appropriate ampacity are used.

Thanks,
Dan

Re: Standard Fuses #8922
04/12/02 10:22 PM
04/12/02 10:22 PM
sparky66wv  Offline
Member
Joined: Nov 2000
Posts: 2,236
West Virginia
Dan,

Thanks, as usual, when one finally understands the "why's", it's easier to remember...

Now it makes sense...

[Linked Image]


-Virgil
Residential/Commercial Inspector
5 Star Inspections
Member IAEI

Featured:

2017 Master Electrician Exam Preparation Combos
2017 NEC Electrician
Exam Prep Combos:
Master / Journeyman

 

Member Spotlight
Radar
Radar
Los Angeles, CA
Posts: 349
Joined: April 2004
Show All Member Profiles 
Top Posters(30 Days)
sparky 23
Admin 20
Potseal 13
Popular Topics(Views)
243,515 Are you busy
180,312 Re: Forum
170,808 Need opinion
Powered by UBB.threads™ PHP Forum Software 7.6.1
(Release build 20180101)
Page Time: 0.013s Queries: 14 (0.003s) Memory: 0.9583 MB (Peak: 1.0887 MB) Zlib enabled. Server Time: 2018-01-17 05:16:37 UTC