Circuit Protection

NOARK circuit protection for domestic, commercial and industrial installations — MCBs, RCBOs, RCCBs and isolators. All devices are CE marked, manufactured to IEC/EN standards and backed by a 5-year warranty. Supplied by Shamrock Electrical Supplies, electrical wholesaler, Rathcoole, Dublin.

Includes Type B RCCBs (Ex9LB63) suitable for EV charge points and PV solar inverters, where sensitivity to smooth DC residual current is required — a capability Type AC and Type A devices do not provide.

Which device do you need?

Device	Protects against	Typical use
MCB — Ex9B125	Overload and short circuit	Final circuit protection. Curve B for resistive loads, C for motors and lighting banks, D for high inrush. 16–100 A, up to 25 kA.
RCBO — Ex9BL-H	Earth fault + overload and short circuit	Per-circuit protection in one 2-module device. 6–40 A, 30/100/300 mA, Type AC or Type A.
RCCB — Ex9LB63 (Type B)	Earth fault, including smooth DC	EV charge points, PV inverters, variable speed drives. 25/40/63 A, 30/100/300 mA, 2 and 4-pole.
Isolator — Ex9I125	Isolation (not a protective device)	Main switch, lockable in the OFF position. 16–125 A, 1 to 4-pole.

Not sure which RCD type your job needs? Read our guide: RCD Types Explained — Type AC vs Type A vs Type B.

Common questions

Do I need a Type B RCD for an EV charger?

You need protection against smooth DC fault current. That means either a Type B RCD upstream, or a Type A RCD where the charge point itself includes a 6 mA DC fault detection device (RDC-DD) to IEC 62955. Check the charger manufacturer's installation instructions to determine which applies.

What is the difference between an RCCB and an RCBO?

An RCCB provides residual current (earth fault) protection only and must be paired with an MCB or fuse for overload protection. An RCBO combines both functions in a single device, so each circuit gets its own residual current and overload protection.

What is the difference between a Type A and a Type B RCD?

A Type A detects AC and pulsating DC residual current. A Type B detects those plus smooth DC residual current and high frequencies up to 1 kHz. Only a Type B is suitable where smooth DC fault current can occur, such as with transformerless PV inverters.

Which MCB curve should I use?

Curve B (3–5 × rated current) for resistive loads and general domestic circuits. Curve C (5–10 ×) for motors, transformers and lighting banks — the most common choice in commercial work. Curve D (10–20 ×) for high-inrush loads such as welding equipment and direct-on-line motor starting.

Are NOARK devices certified for use in Ireland?

Yes. All NOARK circuit protection supplied by Shamrock Electrical is CE marked and manufactured to the relevant IEC/EN standards — EN 60947-2 for MCBs, EN 61009 for RCBOs, IEC/EN 61008-1 and 62423 for RCCBs, and IEC/EN 60947-3 for isolators. Installations must comply with I.S. 10101, the National Rules for Electrical Installations.

Can you supply a complete populated board instead of individual devices?

Yes. We build Equipped Distribution Boards — fully populated consumer units assembled to your circuit schedule, including Type B protection for EV and PV work. Quoted to your specification.

Trade enquiries: sales@shamrockelectrical.ie or (01) 401 9907.