ECN Electrical Forum - Discussion Forums for Electricians, Inspectors and Related Professionals
ECN Shout Chat
Shout Box
Recent Posts
AreMetal Ladders Ever OK For Electrical Work?
by HotLine1. 01/22/18 07:31 PM
by twh. 01/22/18 05:06 PM
VDE 0100 to introduce AFCIs
by sparky. 01/20/18 05:09 PM
MRI LED lights dimmer control replacement - wow!
by Potseal. 01/19/18 08:52 PM
New in the Gallery:
Housebilding DIY wiring
SE cable question
Who's Online Now
0 registered members (), 24 guests, and 12 spiders.
Key: Admin, Global Mod, Mod
Previous Thread
Next Thread
Print Thread
Rate Thread
Reason for tripped fuses #14693
09/29/02 06:06 PM
09/29/02 06:06 PM
moe707  Offline OP
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
Re: Reason for tripped fuses #14694
09/29/02 09:21 PM
09/29/02 09:21 PM
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.



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


Member Spotlight
Posts: 22
Joined: August 2009
Show All Member Profiles 
Top Posters(30 Days)
Admin 21
sparky 15
Potseal 15
Popular Topics(Views)
243,602 Are you busy
180,416 Re: Forum
170,873 Need opinion
Powered by UBB.threads™ PHP Forum Software 7.6.1
(Release build 20180101)
Page Time: 0.010s Queries: 14 (0.003s) Memory: 0.9414 MB (Peak: 1.0585 MB) Zlib enabled. Server Time: 2018-01-23 23:44:59 UTC