When choosing an electrical cable for your applications, you will likely go through the spec sheet first. The data on the spec sheet is observed based on designated cable tests approved by organizations like UL and CSA. Some common types of electrical cable testing are flame testing, UV weather testing, ER testing, and others. Read more about different kinds of cable testing in our guide.

Cable testing is verifying the quality and performance of electrical cables to ensure that the cables will perform as expected in their respective applications. Certification testing for UL and CSA helps measure the parameters of electrical cables against industry standards.

Flame Testing

Flame tests assess the performance of the cables against fire and the way they meet common fire requirements. These tests measure the amounts of smoke and flame produced by a particular electrical cable when exposed to fire. Flame tests used on all North American cables are issued by two organizations, Underwriters Laboratories (UL) and CSA International. The results of flame testing are calculated through various factors, including how long the cable burns, whether it can self-extinguish, and to which point it burns.

What does the CSA standard stand for, and how is it different from UL?

CSA stands for Canadian Standards Association. The standards issued by CSA are similar to the ones produced by UL Underwriter Laboratories, but UL standards only apply to cables manufactured and sold in the United States. CSA ratings apply to cables manufactured and sold in Canada, but this is not the only option with these types of cables. CSA can incorporate international standards, ISO, which makes these cables legally certified across the world. In this sense, CSA tests are more global than UL tests that apply only to one country.

UL Flame Tests

Common UL flame tests are UL VW-1 Vertical Wire Flame Test, UL 910 Plenum Test, UL 1581 Vertical Tray Flame Test, UL 1685, and UL 1666 Vertical Chamber Test. You can learn more about UL VW-1 Vertical Wire Flame Test here, where we dive into the meaning of VW-1 cable marking.

Other UL tests are explained below:

UL 910 is the test necessary for all plenum cables certified in the United States. These cables are meant to be used in tight air-circulated spaces in a building.

During this cable testing procedure, a Stein tunnel test furnace with a length of 25 feet is utilized to hold a rack of cables one foot wide and filled with 24-foot-long cables arranged in a single layer. The test continues for 20 minutes, during which the flame spread is monitored through windows spaced one foot apart. 

This vertical flame test is performed in the vertical cable tray. The cable that passes this test is a tray cable. The cables in this test are attached into a metal ladder cable tray. A ribbon burner is then applied to the cable for 20 minutes. A successful result of this test is if the cable self-extinguishes before reaching the top of the tray.

UL 1685 is a comparable test that additionally has requirements when it comes to smoke emissions. Most tray cables, including PLTC and ITC, pass this test.

This is a test for riser cables, also called the vertical chamber test. The test is performed in a shaft, with a burner at the bottom of the shaft applied to the electrical cable for half an hour. For the cable to pass this test, the flame should not exceed the 12 ft mark.

CSA Flame Tests

CSA has vertical and horizontal flame tests.

FT1 and FT4 - Vertical Flame Tests

Vertical flame tests issued by CSA are FT1 and FT4. FT1 is a standard vertical flame test similar to UL VW-1. This test has five 500-watt flames applied to a cable through short intervals of time. The cable passes the test if it stops burning within the minute after the last flame is applied to them.

FT4 is a tray vertical flame test. The flame is applied to the cable in a vertical tray.

FT2 and FT6 - Horizontal Flame Tests

In horizontal flame tests, the flame is applied to the cable horizontally. The flame is directed at the top of the cable. FT2 test has the cable extinguish itself after a 500-watt flame is applied to it for half a minute. 

FT6 is a flame and smoke test, which is analogical to UL 910.

UV Weather Testing

The UV Weather testing studies how insulation and jacket of the electrical cable performs in outside conditions to make sure that these materials sustain weather conditions. This type of testing is also sometimes known as UV stability testing. 

During the test, the insulation and jacket materials are exposed to UV light and moisture at testing temperatures.

ER Tray Testing

To get an exposed run tray rating ER, the cables are subjected to crush and impact tests that assess the durability and strength of an electrical cable.

To pass crush requirements, the cable is put on a steel rod and crushed with a steel plate. The cable is then analyzed for the contact between circuit conductors or between a circuit conductor and ground conductor/shield.

For an impact test, a steel block is dropped on the cable placed on a steel rod. As a result of this test, there should not be contact between circuit conductors or between a circuit conductor and a ground conductor/shield.

Other Types Of Cable Testing and Non-Certification Tests

Some observational types of testing also applied to electrical cables are:

1. Persulphate test (copper)
2. Annealing test (copper)
3. Tensile test (aluminum)
4. Wrapping test (aluminum)
5. Conductor resistance test (copper and aluminum)
6. Test for the thickness of insulation (copper and aluminum)
7. Overall diameter measurement (copper and aluminum)
8. Tests for different types of resistance of cable, conductor, jacket, or insulation (Oil, Water, Tear).
9. Voltage test
10. Tensile strength tests
11. High voltage tests
12. Insulation shrinkage tests
13. Bending tests
14. Cold impact and cold bending testing
15. Pressure testing at high temperatures
16. Flexing tests

Aluminum, copper, tray, and other types of electrical cables sold by NNC pass important flame, Ul, CSA, and ER tests.