ECN Electrical Forum - Discussion Forums for Electricians, Inspectors and Related Professionals
ECN Shout Chat
Shout Box
Recent Posts
MRI LED lights dimmer control replacement - wow!
by Potseal. 01/19/18 08:52 PM
VDE 0100 to introduce AFCIs
by sparky. 01/19/18 08:03 PM
Video: Inventor of the GFCI self-testing shocks
by Bill Addiss. 01/17/18 11:11 PM
FPE in Germany
by HotLine1. 01/17/18 07:07 PM
Fujifilm Recalls Power Adapter Wall Plugs
by Admin. 01/16/18 07:04 PM
New in the Gallery:
Housebilding DIY wiring
SE cable question
Who's Online Now
0 registered members (), 16 guests, and 13 spiders.
Key: Admin, Global Mod, Mod
Previous Thread
Next Thread
Print Thread
Rate Thread
Page 1 of 2 1 2
1957 Power Tools #168266
08/30/07 02:30 PM
08/30/07 02:30 PM
Admin  Offline
OP
Administrator
Member
Joined: Oct 2000
Posts: 3,481
NY, USA
submitted by HCE727:

[Linked Image]

[Linked Image]

Tools for Electricians:
Re: 1957 Power Tools [Re: Admin] #168281
08/31/07 12:54 AM
08/31/07 12:54 AM
A
aussie240  Offline
Member
Joined: Jul 2005
Posts: 223
Blue Mountains, NSW, Australia
I wonder how many people actually bothered connecting the earth lead on the 2 to 3 pin adaptors supplied with these. In 1957 I imagine there would be a good proportion of 2 pin sockets in use. Of course if the 2 - 3 pin adaptor is lost, one reaches for the pliers, and miraculously the plug now fits.
Hands wrapped tightly around metal cased power tools gives me the creeps.
Does double insulated construction apply in the U.S these days? While obviously modern power tools sold in the U.S are plastic cased like the rest of the world, do they have the 'square within a square' symbol on them to indicate this, or is it only in the 220-240V countries?

Re: 1957 Power Tools [Re: aussie240] #168299
08/31/07 10:35 AM
08/31/07 10:35 AM
M
mamills  Offline
Member
Joined: Nov 2001
Posts: 745
Wharton, Texas, USA
I have a Sears Craftsman drill which I purchased about 15 years ago (well past the point when three-wire cords were common). This drill has a two-wire cord, and the drill states that it is "double insulated". I have yet to really understand this concept. Can anyone explain what is double insulated...the cord, the internals of the drill itself...?

Mike (mamills)

Last edited by mamills; 08/31/07 10:36 AM.
Re: 1957 Power Tools [Re: aussie240] #168300
08/31/07 10:36 AM
08/31/07 10:36 AM
E
electech  Offline
Member
Joined: Feb 2002
Posts: 113
Northern Il
The Skill model 6355 I just saw on a lab bench does have the double insulated (class II) symbol.

I don't like the idea of metal cased cordless tools where the bit or blade could have continuity to the metal case. I am not certain the following is of this construction, as the company did not answer the question I submitted online (which was over yr ago I think - I took no answer as the answer you wouldn't want to hear):

http://www.amazon.com/Black-Decker-RD1440K-Anniversary-Cordless/dp/B00006FX9U

I can not think of a product safety (compliance) reason why a product could not have double insulation from primary parts to the enclosure, and also have a grounded metal enclosure. Though I'd think your odds of being saved from the (hopefully) rare event of a double insulation fault to the chassis might be outweighed by the odds of you getting shocked from ground potential rise.

Re: 1957 Power Tools [Re: mamills] #168302
08/31/07 11:37 AM
08/31/07 11:37 AM
P
pauluk  Offline
Member
Joined: Aug 2001
Posts: 7,520
Norfolk, England
Originally Posted by mamills
This drill has a two-wire cord, and the drill states that it is "double insulated". I have yet to really understand this concept.


Basically, anything and everything which could result in a short causing a metal casing to become energized. For example, where the wiring connects to the motor terminals a broken conductor moving around enough could contact the case. So the whole lot gets put under another insulating cover, hence the double insulation. It's then considered unnecessary to ground the casing since the chances of any internal short causing it to become are energized are extremely small.

Quote
I don't like the idea of metal cased cordless tools where the bit or blade could have continuity to the metal case.


A good point. If I'm going to accidentally hit an energized conductor with a drill bit, I'd much prefer the whole case to be grounded in the old style than to be "double insulated" but with continuity to the chuck.

Re: 1957 Power Tools [Re: pauluk] #168304
08/31/07 12:27 PM
08/31/07 12:27 PM
M
mamills  Offline
Member
Joined: Nov 2001
Posts: 745
Wharton, Texas, USA
Thanks, Paul!!

Mike (mamills)

Re: 1957 Power Tools [Re: mamills] #168325
09/01/07 03:40 AM
09/01/07 03:40 AM
K
KJ  Offline
Junior Member
Joined: Nov 2001
Posts: 52
wow, my dads got one of those 1/2 drills.
damn thing doesnt stop for anything.
weighed a million pounds too.
used to have to use it when i was like 15/16 yo.made ya appreciate it, thats for sure.

Re: 1957 Power Tools [Re: KJ] #168326
09/01/07 05:31 AM
09/01/07 05:31 AM
Trumpy  Offline

Member
Joined: Jul 2002
Posts: 8,231
SI,New Zealand
Actually,
I'd never thought of the metal bit hitting a live cable with one of these drills, although metal appliances have always required an earth (ground) wire in them here.
I owned a Wolf drill that had a metal case on it for a few years, and as KJ said above, these drills don't stop for anything, thankfully my drill never had one of them trigger lock things that most drills seem to have on them these days. I think if it got out of control on you, all you could do is run away from the thing and possibly turn it's power off somewhere. wink

Re: 1957 Power Tools [Re: Trumpy] #168363
09/02/07 10:43 AM
09/02/07 10:43 AM
H
harold endean  Offline
Member
Joined: Feb 2002
Posts: 2,233
Boonton, NJ
Don't laugh guys. My old boss had one of those drills that I had to use when I was a young apprentice just starting out. As for the 3rd wire, well it didn't exist. Somewhere I beileve it was missing and never used. I remember drilling holes in a damp and wet basement. The water had seeped into my shoes and the drill had a small voltage leak. I pulled the trigger and got wacked. So what did my boss do, he gave me a cement cinder block to stand on in order to finish drilling the holes. No more shock! I can't believe how stupid, but lucky I was. It wouldn't happen like that these days.

Re: 1957 Power Tools [Re: harold endean] #168383
09/02/07 08:34 PM
09/02/07 08:34 PM
noderaser  Offline
Member
Joined: Mar 2007
Posts: 404
Portland, Oregon, United State...
My Dad has a whole bunch of metal power tools from the 50s and 60s, although they're all Black & Decker. He's got 3 of the "classic" drill design, plus a skilsaw, heavy-duty drill, right-angle drill, and some other things that escape me at the moment. IIRC, the "classic" designs have a grounded plug; not sure if it actually came with one, or if it's a replacement. Pretty cool collection, and they all still work just fine.

Page 1 of 2 1 2

Featured:

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

 

Member Spotlight
HCE727
HCE727
Delaware County, PA, USA
Posts: 186
Joined: November 2005
Show All Member Profiles 
Top Posters(30 Days)
Admin 20
sparky 15
Potseal 15
Popular Topics(Views)
243,566 Are you busy
180,366 Re: Forum
170,844 Need opinion
Powered by UBB.threads™ PHP Forum Software 7.6.1
(Release build 20180101)
Page Time: 0.022s Queries: 16 (0.006s) Memory: 1.0263 MB (Peak: 1.2065 MB) Zlib enabled. Server Time: 2018-01-20 21:07:58 UTC