Pro Tip: Making Extension Cords

Status
Not open for further replies.

iwire

Moderator
Staff member
Location
Massachusetts
I used to work at a place that used a lot of cord and we often had to make custom extension cords. After watching me struggle for a bit one of the other guys shared this tip with me that really helped me out.

Its just one of those small hints that really works well.

Lets say you want to put these parts together.

IMG_20150311_121552_638_zpsk5dvke9j.jpg


Now my first instinct is to just grab either the male or the female and put it on without regard for which end of the cord I use.

Don't do that. :happyno:

Compare the blunt end of the cord with the cord cap connections.

IMG_20150311_121612_828_zps6ujcldy8.jpg



At one end of the cord they will not match and you will have to cross the conductors inside the cord cap which is a pain as there really is no room for that.

Now take that same cord cap to the other end of the cord and you will find the layout of the conductors matches the layout of the terminals.

Once you do that, and follow the stripping measurements in the instructions you will end up with nice tight cord ends like this.

IMG_20150311_122256_480_zps7pctlwr0.jpg


IMG_20150311_123024_045_zpsdyf0khmd.jpg


It really bothers me when people make up cords and the individual conductors are showing outside the strain relief just because the person could not follow instructions.
 
Thank you...nice tip. :thumbsup:

I used to work at a place that used a lot of cord and we often had to make custom extension cords. After watching me struggle for a bit one of the other guys shared this tip with me that really helped me out.

Its just one of those small hints that really works well.

Lets say you want to put these parts together.

IMG_20150311_121552_638_zpsk5dvke9j.jpg


Now my first instinct is to just grab either the male or the female and put it on without regard for which end of the cord I use.

Don't do that. :happyno:

Compare the blunt end of the cord with the cord cap connections.

IMG_20150311_121612_828_zps6ujcldy8.jpg



At one end of the cord they will not match and you will have to cross the conductors inside the cord cap which is a pain as there really is no room for that.

Now take that same cord cap to the other end of the cord and you will find the layout of the conductors matches the layout of the terminals.

Once you do that, and follow the stripping measurements in the instructions you will end up with nice tight cord ends like this.

IMG_20150311_122256_480_zps7pctlwr0.jpg


IMG_20150311_123024_045_zpsdyf0khmd.jpg


It really bothers me when people make up cords and the individual conductors are showing outside the strain relief just because the person could not follow instructions.
 

jmellc

Senior Member
Location
Durham, NC
Occupation
Facility Maintenance Tech. Licensed Electrician
Good thinking. I have noticed conducter lay before but not thought of reversing ends. The small details really can save you some headaches. Especially true with some of the plugs that give such short shells.
 

GrayHair

Senior Member
Location
Nashville, TN
I was taught this many years ago and the "proper end" was a real head-slap moment. :slaphead:

Repairing extension cords several years ago I was chided for following this. I challenged the guy to see whether using the "proper end" made a difference in speed and finished product. He hurried, I didn't, and I was still quicker and judged to produce a better finished product.

IMO, properly done cord terminations last longer.

Regards!
 

Dennis Alwon

Moderator
Staff member
Location
Chapel Hill, NC
Occupation
Retired Electrical Contractor
I don't make up many cords but I wish you started this thread a few days ago. I had a 4 wire 50 amp cord caps going on a 6/4 sjow cord. I had to do 3 of them. Thanks
 

PetrosA

Senior Member
I wasn't taught this either. When I figured it out a few years back, I was too embarrassed to admit I had only just figured it out and I never told anyone about it thinking I must be the only person left who didn't know. Now I have an easy way to "ease" into it - I'll tell them "Hey, guess what I just learned on the forum!" :cool:
 

electricalist

Senior Member
Location
dallas tx
One year we had a job making up cords for a x mas tree in New York. The ornaments we so big a few people could climb in them,,,anyway I spent DAYS AND DAYS making up cord ends,,,,,crossed wires and all,,,I have anxiety attacks if its brought up.
I thank you iwire and Im a little up set too.
 
one of those awesome "tricks" of the trade. Was never taught this and never gave it a thought. It always was difficult to follow the length of conductor instructions those times (that I now know) I was working at the "wrong" end of the cord. Hopefully, I'll never forget it.

Thanks for sharing this.:)

It would be cool if we had a "tricks of the trade" section of the forum.
 
Great, now that you've spilled the secrets.....

I don't think I ever was taught this, just one day said, "Hmm, why do I have to cross over sometimes?" and took a look. Then I think some twistlocks I got at least 10 years ago had an instruction sheet showing the color rotation.

OTOH, I do very little with MC so probably won't have occurred to me which direction to pull.

The most exciting phrase to hear in science, the one that heralds new discoveries, is not 'Eureka!' but 'That's funny...'
---Isaac Asimov

And, ya- please follow the strip guides and actually tighten the screws. I've got a small pile of melted connectors from people that obviously didn't.
 

mgookin

Senior Member
Location
Fort Myers, FL
Thanks for the tip. I never gave it any thought. I just thought I was doing better work on days that it worked and wasn't on days it didn't work. Now I'll go to the other end! :thumbsup:
 

iwire

Moderator
Staff member
Location
Massachusetts
I believe home made extension cords are prohibited by OSHA.

As long as they are done correctly they are not prohibited by OSHA.

Which is good because finding say a correct length 3 phase 4 wire 30 amp cord set on a shelf somewhere is doubtful.


https://www.osha.gov/pls/oshaweb/owadisp.show_document?p_table=INTERPRETATIONS&p_id=20579
In regard to electrical contractors assembling cord sets at construction sites, the practice is acceptable, provided the assembled cord sets are constructed in a manner equivalent to those that are factory-assembled and approved. (The same approach applies to the General Industry Electrical Standards. However, your question pertained to construction, so the remaining references are to Subpart K of Part 1926.) Criteria for determining whether shop-made cord sets meet existing electrical standards include:

All components must be approved for the purpose by a nationally recognized testing laboratory (1926.403(a)). Individual components must be compatible for use with the other components of the completed assembly.
The cord set must meet all applicable requirements of Subpart K. For example, the assembly must be marked appropriately (1926.403(g)); boxes intended for use in a permanent installation may not be used (1926.403(b)(1)(i)); cords must be connected to devices and fittings so as to provide strain relief (1926.405(g)(2)(iv)); cords passing through holes in enclosures must be protected by bushings or fittings designed for the purpose (1926.405(g)(2)(v) ? fittings designed to fasten cables to metal boxes are not acceptable); and no grounded conductor shall be attached to any terminal or lead so as to reverse designated polarity (1926.404(a)(2)).
The cord set must be assembled by a qualified person.
The wiring of the completed assembly must be checked before the cord set is first used. For example, the following, or equivalent, tests should be performed:

(a) All equipment grounding conductors shall be tested for continuity and shall be electrically continuous.

(b) Each receptacle and attachment plug shall be tested for correct attachment of the equipment grounding conductor. The equipment grounding conductor shall be connected to its proper terminal.
 

domnic

Senior Member
Occupation
Electrical Contractor
Cord set

Cord set

I have never after 30 years heard of this. THANK YOU.
 

SceneryDriver

Senior Member
Location
NJ
Occupation
Electrical and Automation Designer
It really bothers me when people make up cords and the individual conductors are showing outside the strain relief just because the person could not follow instructions.

I agree. It's as though some people don't understand the point of the strain relief at all. If you by chance find a cable that has conductors showing outside the strain relief, either because someone built the cable incorrectly or because it has been repeatedly pulled on, an easy fix is to open up the cord cap and "milk" the outer jacket down towards the end of the cable. It's easier on longer cables because the jacket doesn't have to stretch as much per unit length, but it will work most of the time regardless. It's easy on SJ cable, slightly harder on SO. On some of the signal and control connectors I use, milking the jacket down before closing up the connector is almost a requirement, as you don't have enough free wire to make the solder joints otherwise.

Another trick I use is to give the cable a little shove into the connector before I tighten the strain relief. This ensures that the individual wires aren't taking any pull if/when the cable gets yanked. This is pretty much a necessity when using Pass & Seymour twist locks because of the way the strain relief tightens as you close tighten the plug screws; I don't like those connectors. I much prefer the Hubbell twist lock strain relief design, but I can't always convince the client to spend the extra $$ on them.


SceneryDriver
 
Status
Not open for further replies.
Top