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

ECN Shout Chat
Top Posters(30 Days)
Admin 19
Recent Posts
Anyone hiring inspectors?
by HotLine1. 03/27/17 08:03 AM
Old decora style outlets
by Admin. 03/25/17 11:40 AM
ESA Arc flash course
by TheShockDoctors. 03/24/17 10:15 AM
fuse rejectors
by HotLine1. 03/24/17 07:53 AM
Another Forum Update
by Admin. 03/22/17 03:04 PM
New in the Gallery:
SE cable question
Popular Topics(Views)
231,597 Are you busy
166,422 Re: Forum
160,696 Need opinion
Who's Online Now
1 registered members (gfretwell), 54 guests, and 9 spiders.
Key: Admin, Global Mod, Mod
Previous Thread
Next Thread
Print Thread
Rate This Thread
#14693 - 09/29/02 07:06 PM Reason for tripped fuses  
moe707  Offline
Junior Member
Joined: Sep 2002
Posts: 3
Bay City, MI, USA
At the shop, we pulled wires from a busway box that is protected with 60 Amp. fuses to wire a single phase 220v machine. The wires were pulled to a 60 Amp disconnect switch box. We also pulled wires to a second circuit breaker panel of the load side (not fuse side) of the machines disconnect box. The second panel will serve the lights, receptacles. The common and the ground of the second panel are run separate to the machine disconnect box. Is this ok?

While wiring a baseboard heater that will be protected by a 30 Amp. breaker in the second box (above) my helper and by mistake connected the in and out on the thermostat with the same hot wire and when we turned on to try the heater, it tripped the breaker which is a good sign that the 30 Amp. breaker worked. My problem is this: Why did the two 60 Amp. fuses at the busduct trip? I am kinda concerned.

Thanks for the help and the directions.

Work Gear for Electricians and the Trades

#14694 - 09/29/02 10:21 PM Re: Reason for tripped fuses  
electric-ed  Offline
Joined: Jul 2002
Posts: 175
Generally, fuses operate much faster than circuit breakers due to the inertia of the moving contacts.

I am concerned about your question-
"The common and the ground of the second panel are run separate to the machine disconnect box. Is this ok?"

If you mean that the grounded (neutral) and the equipment grounding conductors are in a different conduit than the hot wires, that is definitely not OK.


Member Spotlight
lil suzi
lil suzi
Posts: 57
Joined: August 2003
Show All Member Profiles 

2017 NEC and Related
2017 NEC
Now Available!

Shout Box
Powered by UBB.threads™ PHP Forum Software 7.6.0
Page Time: 0.012s Queries: 14 (0.004s) Memory: 0.7420 MB (Peak: 0.8572 MB) Zlib enabled. Server Time: 2017-03-28 00:31:55 UTC