After producing the TO/TG/TT range of MCCB's in the 1980's, the original TemBreak range was introduced gradually by around 1990. By 1999 an upgraded range of MCCB's with higher kA and selectivity ratings was introduced and this was known as TemBreak Plus. In 2006 the TemBreak 2 range of MCCB's is being released, and this represents a totally revamped line-up of MCCB's to 630A, covering basic design features, ratings and accessories.

There are a lot of differences, but some of the main differences are:

- Field fit accessories
- Overall the range ranges from 25kA to 200kA, but of special note are the new higher kA ratings in the smaller size breakers without the need for a frame size increase.
- A 250A frame that ranges 12A to 250A
- Common size 400 / 630A MCCB's
- Handles and motors with very clear position indication

The letters AF stand for AMP FRAME. This means that there may be several model types of MCCB that are all the same size, or all the same Amp Frame. For example, TemBreak 2: S160NJ, S160GJ, E250NJ, S250NJ, S250GJ are all rated at different kA ratings, but are physically the exact same size. All 250AF.

Yes, 2 Line side barriers are supplied with 2 pole MCCB's, and 3 with 4 pole MCCB's. Either Interpole barriers or terminal covers must be used for all TemBreak 2 MCCB installations.

The main contacts of the TemBreak 2 MCCB directly drive the toggle movement via a hard mechanism, rather than relying on a spring action. On TemBreak 2 MCCB's, a red and yellow symbol indicates this type of switching.

Yes, there are 3 models, rated at 25kA, 36kA and 65kA. All range from 12A to 125A. The 125A frame is physically smaller than a 250AF.

125AF depth 68mm, 250AF depth 68mm, 400 / 630AF depth 103mm.

All sizes of MCCB with a thermal magnetic trip unit.

50A. The models S250PE and H250NE range 50A - 250A in a 250AF.

Yes, the outline dimensions are the same. There is some difference in the main terminal heights, but that is all.

Not for cable sizes up to 95mm2. The new TemBreak 2, 250AF MCCB's have a 26mm wide terminal space. A standard 95mm lug will fit straight onto the MCCB terminals.

Yes they are the same. They Grey cover is to match the MCCB's in appearance to the new TemBreak 2 MCCB's. The Grey covered 630A - 1600A MCCB's use also the same catalogue numbers.

Yes, but on request only. For several years, NHP will stock a quantity of black covers for conversion of Grey cover types back to Black cover MCCB's if requested.

For another several years the smaller TemBreak 1 MCCB's will be held in stock with accessories continuing to be stocked for a longer period again. For most of 2007 all MCCB sizes will be stocked. After that, NHP will stock the largest kA rating in each of the 125, 250 and 400A frame sizes, with a few exceptions for certain 400AF thermal magnetic and electronic MCCB's.

There is range of TemBreak 2 range of mining MCCB's planned, but they will not be released in 2006. XV400 - XV1250 1000V MCCB's will continue to be available.

They are currently in development.

There will be no add-on earth leakage block for TemBreak 2 MCCB's, as is now the case with TemBreak 1 MCCB's. However there will be a range of TemBreak 2 integral earth leakage MCCB's up to 250A from May 2007. These RCBO (Residual Current Breaker with Overload) MCCB's will offer adjustable earth leakage settings, and other options, all contained within the existing 125A and 250A frame sizes. The new Integral Earth Leakage Circuit Breakers will include 30mA personnel protection, as well as time adjustable machine protection amp ratings.

It should be mentioned that MCCB's 400-1600A will offer the option of ground fault trip, as opposed to the earth fault detection as discussed in the paragraph above.

By removing the top cover, and clicking in the accessory, then replacing the cover. Wires can be run from the sides or bottom via cut-outs in the clip on covers.

TemBreak 2 "heavy duty" auxiliaries and alarm switches have direct opening action contacts. The "general purpose" types do not. This difference is because heavy duty types have a mechanically driven centre bridge contact, where as general purpose types use an internal limit switch which is spring lever actuated.

2 auxiliaries and 1 alarm will fit into MCCB's up to 250A. 3 auxiliaries and 1 alarm will fit breakers 400A / 630A. More detailed information can be found in the T2CPB and technical TemBreak 2 catalogues on this CD.

Yes. 125A and 250A motors have a rotary dial that moves to indicate the main contact status of the MCCB. On 400A / 630A motors, a flag shows the main contact status. On all TemBreak 2 motors, the position indication is directly linked to the MCCB toggle, which in turn is directly driven by the MCCB main contacts.

All TemBreak 2 motors are Padlockable as standard. A padlock can be fitted only when the motor is in the OFF position.

TemBreak 2 variable depth handles (T2HP) are stocked with an IP65 rating. However the user may choose between an IP54 and IP65 handle. Fixed depth direct mount handles, are IP54 as standard, with an IP65 option available on request.

TemBreak 2 handles lock in the off position as standard. An easy field conversion can also be performed to allow locking in any position or none at all.

Yes, an optional padlock attachment is available for this application.

Yes, this is a metal padlock or hasp attachment that fits permanently to the front of an MCCB.

All internal and external accessories can be field fitted except for 400A / 630A cable and link mechanical interlocks, and wire lead terminal blocks. These items can be fitted at your local NHP branch office.

Yes, TemBreak 2 125A and 250A MCCB's will fit to existing XA, XB and XC chassis types. The new TemBreak 2 MCCB's are a lower depth however, so mixing TemBreak 1 and 2 MCCB's is not recommended. TemBreak 1 MCCB's will still be stocked for easy replacement of older MCCB's.

TemBreak 2 MCCB's are available in a 250AF with trip units ranging:

- 12A - 250A with kA ratings to 30kA (20A trip unit min. size)
- 32A - 250A with kA ratings from 36kA to 65kA (50A trip unit min. size)

In those instances where 20A and 32A trip units are to be used in applications with kA requirements from 36kA to 65kA, a 125AF MCCB will be required, and therefore either a 125AF chassis or 125/250A combination chassis such as an XC.

125A and 250A transfer switches using link, slide, or cable interlocks can be made by ordering components. 400A and 630A transfer switches using slide interlocks can also be field assembled. 400A and 630A transfer switches using cable and link interlocks must be factory or local branch workshop assembled by NHP.

The new CPB price list "T2CPB" lists components and quantities to be ordered for field assembly.

Yes, but a limited range, since 125A and 250A, transfer switches using either link, cable or slide interlocks can now be quickly assembled by the user, or switchboard manufacturer. The new TemBreak 2 pocket book "T2CPB" includes a range of commonly requested assembled transfer switch configurations using TemBreak 2 link interlocks. Also listed in the pocketbook are bills of material for the building of transfer switches, including cable types.

No, TemLogic 2 controllers can be set up via soft touch buttons on the fascia of the controller.

Yes, the new controllers are also able to work with TemBreak 1, 630A - 2500A transfer switches.

There is an "interface panel" available from NHP that provides control fuses, control wiring terminals, and a power supply for the controller. Alternatively, the user or switchboard manufacturer can provide equivalent circuitry if they choose.

Yes, a new controller called a TLP2 is available. This is an updated version of the TemBreak 1 relay / timer controller set up to work with TemBreak 2 MCCB's.

A price list "T2CPB" dated October 2006 will be available. This is a short version of the CPB pocketbook that covers TemBreak 2 MCCB's. A technical catalogue on CD plus a printed form of the same technical catalogue will be available by November 2006. An update of the NHP Part C catalogue will be released early 2007 containing more comprehensive information on MCCB's, Chassis, Transfer Switches, MCB's, Panelboard's, ACB's, and Earth Leakage products.

A new version of TemCurve, called TemCurve 6.0 will be available from October 2006. This includes all TemBreak 1 and 2 circuit breakers, and includes increased options and functionality compared to TemCurve 4.3

Additional details: T2CPB page 4-66.

This is explained in section 13 of the Part C catalogue. An explanation is below:

Selectivity:
Also known as "Discrimination", the most basic form of Selectivity is where two circuit breakers are connected in series. A higher amperage breaker is installed upstream, and a lower amperage breaker downstream. Should an overload or short circuit occur downstream, the downstream breaker will trip, but the upstream breaker will not, hence feeding parts of the system which are fault-free. This is the concept of Selectivity.

Selectivity is generally used, for example in critical applications, feeding essential loads. It is important to ensure total installation power is not lost due to a small or minor fault in a sub part of the overall electrical system, for example in a local distribution board. Total power loss could affect vital systems such as in Hospitals or Computer Centre's etc.

The principle of Selectivity (Discrimination) is based upon an analysis of several types of circuit breaker characteristics. These include tripping characteristics (time-current curves), Peak Let Through Current (I_peak) and Energy Let Through (I²T).

Selectivity can be "enhanced" beyond the breaking capacity of the downstream device provided it is backed up by an appropriately selected upstream device, which should not trip (unlatch) under stated conditions.

Cascade (Back-up):
Cascading is achieved by using an upstream device to assist (back-up) a downstream device in clearing a fault current that happens to be greater than the breaking capacity of the downstream device.

In Cascading applications, the upstream device may have to trip (unlatch) in order to give sufficient protection to the downstream device, thus interrupting supply of power to all devices downstream. Therefore, Cascading is generally used in applications involving the supply of non-essential loads, such as basic lighting. The main benefit of Cascading is that in certain circumstances circuit breakers with breaking capacities lower than the prospective fault level, and hence lower in cost, can be safely used downstream provided it is backed-up by the relevant upstream breaker.