Electrical

Electrical Questions? Ask an Electrician Online.

Ask an Expert,
Get an Answer ASAP!

Electrical
This answer was rated:

how do I use a digital ohm tester to take resistance readings

of 120 VAC / 60...
how do I use a digital ohm tester to take resistance readings of 120 VAC / 60 Hz Superior Pro-Heat radiant floor heating cable? The directions require out of the box before installation testing of cable black to white, black to green, white to green, and sensor wire. How do I do this? I have a Sperry DM-210A digital multimeter. Thanks.
Show More
Show Less
Ask Your Own Electrical Question
Answered in 5 minutes by:
11/23/2009
Mike
Mike, Master Electrician
Category: Electrical
Satisfied Customers: 2,742
Experience: Licensed Master Electrician - OnQ Certified Data Voice Audio Video Installer
Verified
To use the OHM setting on your meter, insert one lead in the slot with the icon that looks like a horeshoe, and the other into the COM slot. Then turn the dial to the OHM (again, horeshoe icon) setting, 20K should work ok for your particular reading. Then place one lead on black and the other on the white. You'll get a reading in "ohms" which is resistance. Repeat for each set of wires as the manual requests.. black to green, white to green, etc.

Regards,
Mike
Ask Your Own Electrical Question
Customer reply replied 8 years ago
Hi Mike - Thanks. XXXXX touch the leads to the black and white I get a reading of .05. Does this sound correct? When I touch the leads to black and green or white and green it just displays "1" (i.e., no change in the reading). Does this sound correct?
There is no "correct" reading other than what the manual for your product specifies the resistance should be. Is the cord you are testing connected to the unit? Does your manual specify what resistance reading you should be getting?
Ask Your Own Electrical Question
Customer reply replied 8 years ago
Hi Mike - The cord is not connected to the unit. It is still on the spool right out of the box. I'm supposed to take resistance readings of the cable out of the box before installation and then take resistance readings of the cable after the cable and sensor are fastened to the floor and then after the floor covering is installed. The manual is not clear on what the resistance readings should be. I'm using a spool to cover 25 square feet so there is 118 feet of wire. A chart in the manual indicates that the resistance range is 41-51. The label on the cable indicates that the resistance range is 44-55. Does this help?
Is it specifically saying that you should take a resistance reading from "black to white", "white to green", and "black to green"? Typically, you would want 0 (some meters indicate 1 as "infinite") or "infinite" resistance between those conductors unless they are connected to equipment. I'm wondering if it is asking to you check the resistance of each wire individually by placing one lead on one end of the black wire and the other lead on the other end of the black wire and repeat for each wire. Does this sound like what it's asking you do perhaps?

Try turning the dial to the "200" setting since we are looking for a low range number here and test for resistance both ways if you're unclear and tell me what you get.

Ask Your Own Electrical Question
Customer reply replied 8 years ago

Hi Mike - The manual says to use a quality digital ohm multimeter "able to measure up to 20,000 ohms. To check for breaks, it says "Measure resistance between the black and white cable leads. This measurement should be within the cable resistance range shown on the nameplate label. Measure between the lead wires of the floor sensor. This resistance varies according to the temperature sensed in the tip. A cut or break in the wire is indicated by a resistance of "infinite" ohms (no continuity)."

 

To check for breaks, it says "Measure resistance between the black and green leads and between the white and green leads. These measurements should be "infinite" ohms (no continuity). A cut or pinch in the wire is typically indicated by a resistance value less than the cable resistance range."

 

So, when I touch the ohm meter leads to the black and white wire with the ohm meter set at 20K I get a reading of .05. When I touch the ohm meter leads to the black and green and white and green wires I get "1". "1" is what is displayed in the ohm meter window before I touch the leads to any wire.

 

Am I getting the readings I should get with the cable fresh out of the box?

Frankly, I am confused as to what the manual is asking you to do. You should have 0 ohms from black to white and black to green if you are just measuring resistance from an unconnected cable. Another potential issue here is the meter you are using. While Sperry meters are certainly acceptable for typcial home use, I can't speak for their accracy for resistance tests like you are attempting to perform. That being said, I will "opt out" in hopes that maybe another expert will better understand what it is you need to do here; perhaps they will have a better working knowledge of your particular meter as well. Good luck!

Regards,
Mike

Edited by Mike Pettinato on 11/23/2009 at 4:59 PM EST
Ask Your Own Electrical Question
Paul
Paul, Electrician
Category: Electrical
Satisfied Customers: 805
Experience: 23 yrs as an electrician, self employed contractor, municipal inspector
Verified

Hi

 

Mike asked me to help you out.

 

What the manufacturer wants you to do, is verify that the cabling is in good shape before it gets installed and then to recheck it before you install your tile or flooring.

 

So the first step will be, to make sure there not any readings from black to ground or white to ground and that you have a reading between black and white.

 

Does the reading between black and white equal the resistance marked on the product lable?

Ask Your Own Electrical Question
Customer reply replied 8 years ago
Hi Paul - Thanks. It appears that I'm not getting any readings from black to ground or white to ground. So this appears correct. The reading I get between black and white says ".05" ohms. The product label says the resistance range (ohms) of the cable is 44-55. I have the ohm meter set to 20K, so is ".05" an ok reading? Maybe there isn't any acceptable reading just as long as I maintain a .05 reading throughout the installation and I don't exceed 44-55 ohms once it is connect to power?

Yes

 

If you set the meter to 1K or auto you will see the reading is closer to the tag.

 

After you install the cable check it again to make sure the readings did not change.

 

Let me know if you need more help.

 

Paul

Paul
Paul, Electrician
Category: Electrical
Satisfied Customers: 805
Experience: 23 yrs as an electrician, self employed contractor, municipal inspector
Verified
Paul and 87 other Electrical Specialists are ready to help you
Ask your own question now
Ask Paul Your Own Question
Paul
Paul
Paul, Electrician
Category: Electrical
Satisfied Customers: 805
805 Satisfied Customers
Experience: 23 yrs as an electrician, self employed contractor, municipal inspector

Paul is online now

A new question is answered every 9 seconds

How JustAnswer works:

  • Ask an ExpertExperts are full of valuable knowledge and are ready to help with any question. Credentials confirmed by a Fortune 500 verification firm.
  • Get a Professional AnswerVia email, text message, or notification as you wait on our site. Ask follow up questions if you need to.
  • 100% Satisfaction GuaranteeRate the answer you receive.

JustAnswer in the News:

Ask-a-doc Web sites: If you've got a quick question, you can try to get an answer from sites that say they have various specialists on hand to give quick answers... Justanswer.com.
JustAnswer.com...has seen a spike since October in legal questions from readers about layoffs, unemployment and severance.
Web sites like justanswer.com/legal
...leave nothing to chance.
Traffic on JustAnswer rose 14 percent...and had nearly 400,000 page views in 30 days...inquiries related to stress, high blood pressure, drinking and heart pain jumped 33 percent.
Tory Johnson, GMA Workplace Contributor, discusses work-from-home jobs, such as JustAnswer in which verified Experts answer people’s questions.
I will tell you that...the things you have to go through to be an Expert are quite rigorous.

What Customers are Saying:

You did one super job of explaining to me everything there is to know about this fridge. I'm looking forward to asking you questions in the future.

JimmyBagley, IA

Wonderful service, prompt, efficient, and accurate. Couldn't have asked for more. I cannot thank you enough for your help.

Mary C.Freshfield, Liverpool, UK

This expert is wonderful. They truly know what they are talking about, and they actually care about you. They really helped put my nerves at ease. Thank you so much!!!!

AlexLos Angeles, CA

Thank you for all your help. It is nice to know that this service is here for people like myself, who need answers fast and are not sure who to consult.

GPHesperia, CA

I couldn't be more satisfied! This is the site I will always come to when I need a second opinion.

JustinKernersville, NC

Just let me say that this encounter has been entirely professional and most helpful. I liked that I could ask additional questions and get answered in a very short turn around.

EstherWoodstock, NY

Thank you so much for taking your time and knowledge to support my concerns. Not only did you answer my questions, you even took it a step further with replying with more pertinent information I needed to know.

RobinElkton, Maryland

< Previous | Next >

Meet the Experts:

Mike

Mike

Master Electrician

2,742 satisfied customers

Licensed Master Electrician - OnQ Certified Data Voice Audio Video Installer

Jason

Jason

Service Technician

3,940 satisfied customers

Over 20 years of experience in all types of installations, troubleshooting, and repairs.

Mike G.

Mike G.

Master Electrician

7,603 satisfied customers

Proven Professional 48 years Experience

Kevin

Kevin

Licensed Electrical Contractor

3,715 satisfied customers

30 years Licensed Electrical Contractor in Illinois, Adjunct College Electrical Instructor, Former Electrical Inspector, Diploma: Digital Electronics, FCC Technician License

AssuredElectrical

AssuredElectrical

Master Electrician

3,264 satisfied customers

Contractor-42+ Years in the ElectricalTrade

electrifier

electrifier

Master Electrician

1,458 satisfied customers

Electrical contractor and electrical inspector for over 24 years with phone and networking expertise

Rich

Rich

Master Electrician

1,115 satisfied customers

Over 35 years residential, commercial, industrial wiring, install, troubleshoot, service, maintain

< Previous | Next >

Related Electrical Questions
The house I live in has one (1) 100 amp circuit
the house I live in has one (1) 100 amp circuit breaker...how is it possible to lose some of the electrical power but not all of it??… read more
Kevin
Kevin
Licensed Electrical Contractor
Diploma
3,715 satisfied customers
We have a fan light combo remote controlled only and the
We have a fan light combo remote controlled only and the light button does not work. We see a burned spot on the the board. CHQ8BT7053T … read more
Kevin
Kevin
Licensed Electrical Contractor
Diploma
3,715 satisfied customers
I have the symptoms of a circuit but no circuit has tripped.
I have the symptoms of a blown circuit but no circuit has tripped. I thought maybe a black wire had popped somewhere along the circuit and that was causing the absence of power. All the whites show co… read more
Mike G.
Mike G.
Master Electrician
Vocational, Technical or Trade Scho
7,603 satisfied customers
I am having issues getting electricity to my GFCI outlet.
Hi, I am having issues getting electricity to my GFCI outlet. The light is illuminated green, but when I plug something into it, it doesn't flip on … read more
Sam I
Sam I
Electrician
B.S.
381 satisfied customers
I have a three-way switch with two hot wires (purple) and a
I have a three-way switch with two hot wires (purple) and a green and black wire. I want to install a dimmer switch but have tried a variety of wiring connections. Nothing worked - the ceiling light t… read more
Mike G.
Mike G.
Master Electrician
Vocational, Technical or Trade Scho
7,603 satisfied customers
I can't access the referenced website 2 hours. I just want
I can't access the referenced website http://www.globalmarket.com/jingneng/Products-741_1-Dimmer.html … read more
Sam I
Sam I
Electrician
B.S.
381 satisfied customers
Bought a late 1800's house along with a mess of electrical
Hi, Bought a late 1800's house along with a mess of electrical issues. The ceiling light fixtures were literally hanging by the wires, so started about replacing them with purchased new lights from Lo… read more
Kevin
Kevin
Licensed Electrical Contractor
Diploma
3,715 satisfied customers
I'm having trouble getting power back on to my trailer I
I'm having trouble getting power back on to my trailer I went to turn off the main switch to the break box and when I flipped it back on nothing happened I even reset the main switch outside twice bef… read more
Kevin
Kevin
Licensed Electrical Contractor
Diploma
3,715 satisfied customers
I've got an electronic circuit that signals when the circuit
I've got an electronic circuit that signals when the circuit is completed by a light that goes on. Is there a chip that exists that could alert me on my cell phone? … read more
Sam I
Sam I
Electrician
B.S.
381 satisfied customers
House is 40 years old and has a modern 200 Amp breaker
House is 40 years old and has a modern 200 Amp breaker system. I have a 20A circuit that feeds a number of switches in one box. One of the switches feeds 2 lights in the carport. About 3 weeks ago, th… read more
Kevin
Kevin
Licensed Electrical Contractor
Diploma
3,715 satisfied customers
I have a JFY solar inverter that has fault on it. "DCinj
hello, I have a JFY solar inverter that has fault on it. "DCinj Failure" can you tell what this means? Is it a fault with the inverter or with the solar panels? … read more
Kevin
Kevin
Licensed Electrical Contractor
Diploma
3,715 satisfied customers
I'm adding a RV temp power supply. It is a 150' run. The
I'm adding a RV temp power supply. It is a 150' run. The plug from the RV says 120 volt 30 amps. Do I understand that with over current protection that the max draw would be 24 amps? Is then 24 amps w… read more
Sam I
Sam I
Electrician
B.S.
381 satisfied customers
Show wire diagrams. for 80 gallons air compressors. Today.
show wire diagrams. for 80 gallons air compressors … read more
Sam I
Sam I
Electrician
B.S.
381 satisfied customers
I have a two light flood light receptacle and I would like
hello,I have a two light flood light receptacle and I would like to put a photocell on one of the two light and have the other light wired for manual on/off. Is that possible and if so, how?… read more
Sam I
Sam I
Electrician
B.S.
381 satisfied customers
I have 2 light switches in my dining room. Tonight. Maybe
i have 2 light switches in my dining room JA: I'll do all I can to help. How long have you been dealing with this? Customer: tonight JA: Do you plan on doing the work yourself? Customer: maybe JA: Any… read more
Mike G.
Mike G.
Master Electrician
Vocational, Technical or Trade Scho
7,603 satisfied customers
I'm trying to install a B2-Switch to replace a conventional
I'm trying to install a B2-Switch to replace a conventional switch. This is to allow for surface wiring to what will be a new light. I'm having trouble with the wiring getting in the way and the switc… read more
Sam I
Sam I
Electrician
B.S.
381 satisfied customers
How to wire 110v thru transformer to 12v pool light. 1 week.
how to wire 110v thru transformer to 12v pool light … read more
Mike G.
Mike G.
Master Electrician
Vocational, Technical or Trade Scho
7,603 satisfied customers
We have two sockets in our kitchen that aren't working...
We have two sockets in our kitchen that aren't working... They are between the counter and the cabinet. One is a gfi and the other is a normal socket. Neither is working. We replaced them both still n… read more
Mike G.
Mike G.
Master Electrician
Vocational, Technical or Trade Scho
7,603 satisfied customers
Disclaimer: Information in questions, answers, and other posts on this site ("Posts") comes from individual users, not JustAnswer; JustAnswer is not responsible for Posts. Posts are for general information, are not intended to substitute for informed professional advice (medical, legal, veterinary, financial, etc.), or to establish a professional-client relationship. The site and services are provided "as is" with no warranty or representations by JustAnswer regarding the qualifications of Experts. To see what credentials have been verified by a third-party service, please click on the "Verified" symbol in some Experts' profiles. JustAnswer is not intended or designed for EMERGENCY questions which should be directed immediately by telephone or in-person to qualified professionals.

Disclaimer: Information in questions, answers, and other posts on this site ("Posts") comes from individual users, not JustAnswer; JustAnswer is not responsible for Posts. Posts are for general information, are not intended to substitute for informed professional advice (medical, legal, veterinary, financial, etc.), or to establish a professional-client relationship. The site and services are provided "as is" with no warranty or representations by JustAnswer regarding the qualifications of Experts. To see what credentials have been verified by a third-party service, please click on the "Verified" symbol in some Experts' profiles. JustAnswer is not intended or designed for EMERGENCY questions which should be directed immediately by telephone or in-person to qualified professionals.

Show MoreShow Less

Ask Your Question

x