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Support System for International Standards

What Is the Support System for International Standards? | Checklist | PowerBOX Circuit Units | About Each Standard

What Is the Support System for International Standards?

Tsuruta ElectricのSupport System for International Standards


To which countries is the product being exported?

For the products to be exported, the various regulations are being tightened. In order to clear these export regulations, it is necessary to manufacture the products in conformity with the technical standards. Therefore, it is important to understanding correctly the regulations in the country to which the products are exported.

What kind of structure has the device?

According to the device or system, the standard to be applied comes to be different. When the extremely strict standards will be applied, it could cause the cost increase and lead to the lowering of the price competitiveness on the world market. This inquiry is made to select the exact standard according the device or system.

CE-Marking, or UL?

There is a big difference basically in the system itself between CE–Marking and UL. Therefore, the approach for the export to Europe and USA comes to be quite different. It is also possible to obtain the approval for both standards for the product according to your request.

What is the basic requirement for the transformer?

The main point of the transformer design is the basic specification. It is required to inform us of your requirements in details for the load, capacity factor, housing etc. We will develop the transformer meeting your requirements and purpose.

Is EPO circuit required?

The safety circuit such as emergency cutout circuit is required to the primary power module, and the transformer itself is required with the high-grade insulation. We can supply the transformer including such a safety device or other special requirements.

PowerBOX Circuit Units

1.Voltage conversion and capacity (Selection of transformer) 2.Transformer protection system:Breaker/fuse 3.Emergency protection system: Emergency cutout circuit EPO by means of temperature sensor 4.External interlock incorporated 5.Switchover by Tap(or External switching) 6.Measures against power outage of the control circuit

About Each Standard

In case of CE-Marking

The conformity with the regulations based on the directive concerned is required. The low voltage directive is applied to the device for 600V and below. The absolute condition for placing the CE mark is the conformity with low voltage directive. CE-Marking can be recognized by the approval test of the third party accrediting organization, or “Self-declaration” by the manufacturer can be also possible depending on the category. The TUV mark is valid as a mark of the third party accrediting organization, but the cost of the approval test and the annual maintenance cost of the mark should be taken into account.

Regulations in Various Countries

Obtaining the safety regulation for various countries and undertaking the approval tests, we can supply our customers with the most suitable transformers and POWER BOX to the requirements.
IEC (International Electrotechnical Commission)
EN (European Norm)
UL (Underwriters Laboratories)
SEMI (Semiconductor Equipment and Materials Institute)
NFPA 70/79 (National Fire Protection Association)
NEC (National Electrical Code)


SCCR means “Short Circuit Current Rating”, and the visual indication of SCCR on the name plate of industrial control panel is mandatorily required by NEC2005, Article 409. This is different from the idea that the breaking capacity of the main breaker on the primary side can be simply indicated, as already considered in Japan and Europe, and it should be noted that this is basically different from the simple indication system.
This requirement to indicate SCCR is limited at present to the USA only, but it is possible that this trend could be taken into the regulation in the other countries or the internal regulation of the multinational enterprises which have their factories in various countries. As a background of SCCR regulation, when the installation of the factory equipments was planed, the staff member of the building and repairs section, who has to protect the machine operators from the short-circuit trouble of the control panel could not judge the risk of the short-circuit trouble because SCCR was not indicated on the name plate.
Recently, the plant layout came to be frequently changed in short cycle because of the productivity improvement. As a result of this, the distance from the machine to the transformer was changed accordingly, and it happened that the short-circuit current at the short-circuit trouble showed a big difference due to the difference in the wiring distance and the cable diameter. (* See 1) Thus, the attention to the risk of the short-circuit trouble caused by moving the machine to other place came to be required.
In the manufacturing process, it is an important factor to watch and check always the risk of the trouble and the operation safety. Therefore, in the USA, the basic regulation for SCCR was decided by UL508(Standard for Industrial Control Panels) at first in April, 2001.

In case of our POWER BOX with the specification for the USA, SCCR is indicated on the name plate. However, the additional indication of SCCR to the existing facilities is not required. The machines and facilities newly exported to the USA are required to indicate SCCR on their name plates. The decision on the specification for SCCR depends on the information or specification from the end user, but the indication of SCCR is under the obligation irrespectively of the information of SCCR. The subject of SCCR could be a target of AHJ factory inspection in each state in USA, and it is very important how to decide the specification for SCCR value.

Regarding SCCR, what is different from the former way of thinking is to indicate the smallest value of the short circuit current for each component (breaker, electromagnetic switche, contactor, terminal block, ammeter, switch and others) which composes of the control panel. Therefore, when designing the control panel, it is necessary to consider the value of SCCR from the time of selecting these components.

As our POWER BOX is positioned as a motor circuit of the control panel, the indication of SCCR is required as a mandatory condition. Discussing the subject of SCCR with our customer at the initial stage of the development, we decide the effective indication of SCCR. When it is required to take the SCCR value of the existing control panel, our POWER BOX has an advantage that there is no need to change the former control panel in the standard specification, to make the higher SCCR value possible.
∗1 Calculation of short circuit current: The short circuit current is determined by the impedance through the cable diameter and distance between the transformer at the network connection point and the place of the working machine.
Calculation of the short circuit current on the secondary side of Transformer:
Calculating the Secondary rated current from VA, it is devided by Z%(Impedance voltage of the transformer) and multiplied by 100.
SCCR Specification (Rated short circuit current) : Please give us the value of KA.

Answer to various problems

Prompt measures

  • Contact,Estimation