Electromagnetic Industries is committed to the highest standards of quality and safety. Our products are independently tested and certified to meet rigorous industry requirements.
UL Accredited
UL Certification
Look for the UL mark on our products for confirmation of our UL certification. We follow local, as well as federal, environmental regulations and safety standards.
UL File E238418 — Ground Fault Relays & Ground Fault Sensors UL File E238872 — Current Transformers & Potential Transformers / Voltage Transformers UL File E510552 — Protective Relays
Our quality management system is certified to ISO 9001:2015, the international standard for quality management. This certification demonstrates that EI maintains a systematic approach to quality across every aspect of our operations — from design and procurement through manufacturing, testing, and delivery. Our ISO certification is maintained through regular third-party audits to ensure continuous compliance and improvement.
Warranty & Standard Conditions of Sale
Electromagnetic Industries warrants to the Purchaser of the equipment/product that the equipment will be free from defects in material or workmanship and that the product will be of the kind and quantity specified in the Purchase Order.
Warranty applies within one year (365 days) from shipment date unless otherwise specified on invoice. Defects are corrected through repair or replacement.
The liability of Electromagnetic Industries under this warranty (except as to title), or for any loss or damage to the equipment whether the claim is based on contract or negligence, shall not exceed the cost of correcting defects in the equipment as herein provided.
Sales & similar taxes are the responsibility of the Purchaser
Quotes valid 30 days from issue date; prices subject to change without notice
Standard payment terms: net 30 days from invoice date
Cancellation requires written notice and payment of cancellation charges
Returns: 25% minimum deduction plus transportation; unused catalog items only, in original packaging, within 6 months
Delivery dates are approximate; carrier assumes risk upon shipment
Claims for loss or damage must be directed to the carrier; shortage claims within 30 days
Frequently Asked Questions
There are many different applications (and methods) for using our products. While we can provide technical specifications and general guidance, we may not be able to give direct advice for how to set up your particular system. Please contact our technical support team and we will assist where we can.
Relaying accuracy class designated by "C" describes the capability of the transformer. The ratio error is limited to 10% at any current from 1 to 20 times rated secondary current.
Yes. Common alternatives include 1A, 0.5A, 0.2A, 0.1A, and 0.08A secondary currents. Please refer to individual product datasheets for available options or contact us for custom requirements.
In most instrument transformer applications where the CT is being used for measurement of amperage magnitude only, the CT will work regardless of direction of current flow through the CT. For phase angle applications, however, direction may be critical — the H1 terminal should face the source.
Thermal Rating Factor indicates the overload capability of a current transformer. It shows the safe continuous current multiples over the nameplate rating that the CT can carry without exceeding its temperature rise limits.
Divide the primary current by the secondary current to determine the turns needed. Consult the schematic diagram on the product datasheet for proper tap connections for your specific ratio.
These set-points are determined by the level of protection required. Refer to your switchgear manufacturer or engineer for application-specific settings. UL 1053 and NEC Section 230 limits may apply to your installation.
For three phase systems where there is a Neutral present, all three phases and the Neutral MUST go through the sensor for proper operation.
Zero Sequence sensors are used for detecting a ground fault by measuring residual current, which is the product of the vector summation of the three phases.
Ground fault relays offer several advantages: quick reset capability, adjustable time delays and amperage levels, no inventory management (unlike replacement fuses), inverse time curves, zone interlocks, fault indications, and push-to-test features.
Standard units require full time delay for a trip. Linear curve reduces delay 50% per amperage doubling. Logarithmic curve reduces delay 75% per doubling.
The rate of discharge depends on the load across the output. The time for discharge can be determined by using the formula: t = -RC × ln(V/V0).
No. The CTD is designed to be a source of DC power in the event of a power failure only. It is not intended for use as a continuous DC power supply.
