UL是Underwriters Laboratory的缩写，同时也是美国的一个安全标示符号，Underwriters Laboratory制定了许多美国国家承认的标准，如果你的产品通过UL标准的所有测试并获得证书，则产品就能标UL符号;CUL是加拿大的安全符号,它与CSA是相当的,都是加拿大承认的安全符号,不过cUL是UL实验室按加拿大的安全标准对产品测试后符合的要求的产品所需标识的安全标志!
如果要美国和加拿大一起做,可以打cULus 标签. 表明两个国家都已经做了认证.
UL和CUL都是UL实验室的的一种列名,只不过适用国家不一样,UL适用于美国,CUL适用加拿大,你可以单独申请,当然你也可以在申请UL的时候可同时申请CUL(如有需要),费用都是一样的,但你要注意你产品本身的一些信息资料是否都满足二者的要求.当你通过二者的要求后,UL会给你一个列名号,之后你就可以在UL全球网站查到贵司的做过列名产品的信息.UL跟CUL的列名号是同一个,但在这个号下面有产品的两个信息,一个是for US的,一个是for canada.做过这个列名后,您的产品可以说在北美市场上是通行无阻了

The differences between the UL and CUL certifications

UL stands for Underwriters Laboratory, is also a security identification symbols for America. Underwriters Laboratory has developed a number of standards recognized by the United States. If your products pass all the tests by UL standard and obtain the certification, the product will be able to standard UL symbol. CUL is a symbol of Canada's security, it is considerable with CSA, are all recognized symbol of safety in Canada. CUL is a safety sign that UL test the products according to Canadian safety standards to meet the requirements of product identification safety signs!

UL and CUL are all column names of UL lab , but  they are for different countries UL applies to the United States, CUL applies to Canada. You can apply individually, you can also apply for UL and CUL at the same time(if necessary), and the costs are the same.

If you have the certification of UL and CUL,your product  will be is unimpeded access

in the North American market.