Add-On Ground-Fault and Earth-Leakage Modules

Class 931, 940, 960

Micrologic™ Add-on Ground-Fault Module (GFM)

GFM250 with Optional GFM25CT

The Micrologic Ground-Fault Module (GFM) is a UL Listed/CSA Certified circuit breaker accessory which protects equipment from damage caused by ground faults. It is an add-on module which, when connected to a PowerPact H- or J-frame thermal-magnetic circuit breaker only, provides ground-fault sensing and ground-fault relay functions.

HD/JD ground-fault modules feature:

  • Adjustable ground-fault pickup levels

  • Adjustable ground-fault time delays

  • Integral ground fault push-to-test feature

  • Ground-fault indicator (mechanical for local, contacts for remote)

  • All GFMs are supplied for I-Line™ mounting as standard, easily convertible to unit mount by removing the I-Line bracket

  • Fault-powered (through the sensing current transformer) for electronics, shunt trip, and integral test feature. Meets NEC 230.95(C)

  • A 12 Vdc shunt trip module (Catalog No. S29382) is required in the circuit breaker. This may be field installed or factory installed when the circuit breaker is ordered with an -SN suffix.

  • UL 1053 — Ground-fault Sensing and Relaying Equipment

The GFM system requires the following:

  • H-frame (15–150 A) or J-frame (150–250 A) molded case circuit breaker

  • Shunt trip is required for the function of the GFM (may be factory-installed or field-installed)

  • Bus bar connection (terminal nut inserts) for OFF end of circuit breaker

  • Optional neutral current transformer, catalog number GFM25CT (must be ordered for 4-wire applications).

    note

    Ground-fault modules cannot be used for alarming only.

Module/Enclosure Selection Chart [1]

Companion Circuit Breaker Prefix

Cat. No. [2]

I-Line
Switchboard

Ground-fault Pickup
Adjustment Range

HD, HG, HJ, HL

GFM150HD

LA

20–100 A

JD, JG, JJ, JL

GFM250JD

LA

40–200 A

Accessories

H & J

GFM25CT

Optional Neutral Current Transformer (required for 4-wire loads)

Earth Leakage Module (ELM) for PowerPact H- and J-Frame MCCBs

I-Line J-Frame with ELM Installed

The Earth Leakage Module (ELM) is an add-on module which, when connected to a PowerPact H- or J-frame MCCB, provides low-level ground-fault sensing and ground-fault relay functions.

Because these ELMs are highly sensitive (30 mA to 3 A), they provide much greater protection than GFMs (20 Amps to 200 Amps sensitivity). The ELMs provide greater protection of control circuits and other sensitive equipment. The associated circuit breaker must have a 48 Vdc shunt trip, which may be field-installed (kit S29392) or factory-installed (suffix –SP) in the H- or J-Frame circuit breaker.

Add-on Earth Leakage Module (ELM) Features:

  • Adjustable ground-fault pickup levels as low as 30 mA

  • Adjustable ground-fault time delays from instantaneous to 500 msec
    (Time delay can be applied to the 30 mA setting)

  • Integral ground fault push-to-test feature

  • Ground-fault indicator; pop-up button for local status and contacts for remote indication (to be used only with the tripping option)

  • All ELMs are supplied for I-Line™ mounting and are easily convertible to unit-mount by removing the I-Line brackets

  • Three poles; 240 to 600 Vac maximum: 3-wire applications only (no neutral)

  • Line-power obtained through internal bus to provide power for electronics, shunt trip, and integral test feature.

  • A shunt trip is required in the circuit breaker; it may be field-installed or factory-installed in the PowerPact H and J circuit breakers.

  • UL 1053 – Ground-fault Sensing and Relaying Equipment

ELM Selection Chart [3]

Companion Circuit Breaker [4]

Enclosure Space Required I-Line Switchboard

Pick-Up Adjustment Range

Catalog Number

Prefix

Size

HD, HG, HJ, HL

15–150 A

LA

30 mA–3 A

ELM150HD

JD, JG, JJ, JL

150–250 A

LA

30 mA–3 A

ELM250JD

Footnotes

  1. At 250 A, the GFM250JD can be used with 80% rated circuit breakers only.
  2. See Supplemental Digest Section 3 for additional GFMs.
  3. At 250 A, the ELM250JD can be used with 80% rated circuit breakers only.
  4. For Factory Installation of ELM Module: For termination designation (3rd letter of catalog number) use ONLY “M”. Add factory installed 48 Vdc shunt trip (suffix SP) to breaker plus suffix VL or VM.

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