CHs Controls Electrical equipment, North American standards

Product adaptation, the key to success in North America!

CHS Controls has since 30 years been working with the export industry in the Nordic countries in adapting its electrical equipment according to North American standards. Our knowledge of current standards, our market-leading suppliers, combined with broad experience has assisted many export companies to success in the North American market.

The best way to get a satisfied customer is when the supplied product meets the final user´s expectations. A new export market, like North America, involves new challenges. The customer´s expectations on parts of the product - the electrical equipment - may not be in line with expectations from our domestic market. Awareness and consultation may be the difference between success and failure.

Product adaptation is the key when exporting to North America. Adaptation comprises both fulfillments of applicable regulations and to meet customer’s demands/expectations. It is not any insurmountable obstacle, you reach far with awareness and common sense.

 

Products according to North American standard

North American standard applies mainly for products used in USA, Canada and Mexico. But also other parts of the world use standards that are based on the North American, with some variations. The North American market is approximately of the same size as the European.

For marketing and sales of electrical equipment to North America product adaptation is of major importance. Product adaptation means complying with valid standards and regulations as well as satisfying the final customer's demand for well-known products and easy access to spare parts. It is also important to recognize product responsibility, something that will strike if you meet misfortune. Try to avoid misfortune by obtaining knowledge and seeking aid from those who have knowledge and experience.

Electrical safety in USA is decided on federal, state, regional and local level. Federal regulations are of general nature and compliance is required. Local regulations can differ between states and regions. Much of the differences are due to different climate conditions etc.

USA and Canada have similar regulations but a CSA approval is not valid in USA and the other way around. There are possibilities in both countries to test a product and achieve for example a CSA(us) approval.

All US flagged ships must have equipment that meets standards developed by US Coast Guard.

Short-circuit current – SCCR

SCCR is defined by NEC (National Electrical Code) as the maximum short-circuit current a component or assembly can safely withstand. NEC requires control panels and other equipment to be marked with SCCR.

Equipment with insufficient SCCR can pose a risk to personnel and equipment or create a fire hazard. In 2017 the NEC (National Electrical Code) had included several new short-circuit protection requirements. The most significant changes will require that the available fault current at the location where the equipment is installed is marked and documented. These changes will allow installers, inspectors to verify that the installed equipment SCCR is equal to or greater than the available fault current. When it comes to control panels, UL 508A Supplement SB establishes an approved method that defines how equipment SCCR is determined.

 

 

Current-limiting devices - Strengthening the weakest SCCR link!

The UL 508A Supplement SB provides an analysis method that considers the “weakest link” as the basis for the determining equipment SCCR; the equipment SCCR is limited to the lowest rated component SCCR or lowest rated overcurrent protective device interrupting rating in the control panel.

There are three key considerations to determining equipment SCCR

  • Component SCCRs
  • The interrupting rating of the overcurrent protective devices
  • The effect of current-limiting devices in the feeder circuit

According to UL 508A SB4.3, current-limiting devices in the feeder circuit can be used to increase branch-circuit component ratings. The peak let-through current of a current-limiting overcurrent protective device in the feeder circuit is compared to the downstream branch circuit component SCCR. If the peak let-through at a selected prospective short-circuit current is less than or equal to the component SCCR, then the component SCCR can be raised to the selected prospective short-circuit current.

Current-limiting fuses shall be approved according to UL 248 and be marked with “Current Limiting” for example class J, CC, RK1, RK5, T and L fuses. The value for the peak let-through current must be determined from Table SB4.2 in UL 508A.

Another alternative is the use of current limiting MCCBs according to UL 489. The MCCB shall be marked “Current Limiting”, the value for the peak let-through current is provided by the manufacturer.

We provide a full range of fuses and fusible switch disconnectors from Eaton Bussmann Series and UL 489 current limiting MCCBs from Eaton.