Question 1

What is the maximum ambient temperature that a transformer can be installed in?

Accepted Answer

Issue:Ventilation and cooling is an important issue in the installation and operation of transformersProduct Line:LV TransformersEnvironment:Applies to all Low Voltage (LV) Transformers by SquareD/Schneider ElectricCause:Excessive heat is destructive to transformersResolution:The average ambient temperature for a transformer over a 24 hour period should not exceed 30 degrees Celsius. For instance, if the transformer ambient temperature was 40 deg. C for 12 hours, then the transformer must not exceed 20 deg. C for the remaining 12 hours to average a 30 deg. ambient temperature.If the average ambient temperature exceeds 30 degrees Celsius, the derating factor is 0.4% reduction of VA for every degree Celsius above 30 degrees Celsius per IEEE C57 12.96. The IEEE formula that is used to derive the 0.4% factor is valid only up to an AVERAGE of 50 degrees Celsius. Also, using transformers above their listed ambient temperature can shorten the life of the transformer. Due to the number of other factors involved, such as loading, frequency of use, and humidity, no data exists on how high ambient temperatures affect the life of a transformer.

Question 2

Can a 3-phase QO load center be used on a  240 V "high leg" system?

Accepted Answer

Issue:ApplicationProduct Line:QO Load CenterResolution:Yes, but it is important to understand some limitations. This "high leg" delta system referred to is actually a 3 phase, 4 wire, 240/120 V delta system. It has a number of common names, including high leg, wild leg, stinger leg, etc. This system provides 240 V phase-phase power between all 3 phases, plus 120 V phase-neutral power on 2 of the 3 phases. The problem, however, is with the phase-neutral on the 3rd phase: it measures 208 V, which is not a usable downstream voltage since it is too high. This is what gives the system its nickname, high leg. This high leg is commonly the B phase, but could be the A or C phase.Selecting QO breakers for this system must be done carefully. Here are some guidelines:1-pole QO Breakers Standard 1-pole QO breakers have a voltage rating of either 120/240 V (e.g., QO120) or just 120 V (e.g. QO120GFI). These should only be applied on phases measuring 120 V phase to neutral, never on the phase measuring 208 V phase to neutral. 2-pole QO Breakers Standard 2-pole QO breakers have a voltage rating of 120/240V (e.g., QO240). These should only be applied on phases measuring 120 V phase to neutral, never on the phase measuring 208 V phase to neutral.Special 2-pole QO breakers with "H" suffix have a voltage rating of 240 V (e.g., QO240H). These may be applied on any of the phases, including the high leg phase. 3-pole QO Breakers Standard 3-pole QO breakers have a voltage rating of 240 V (e.g., QO330). These may be applied on any of the phases, including the high leg phase. NOTE: The installer should be careful to follow NEC and/or local electrical codes regarding the wiring, marking, and usage of this system.

Question 3

Is a Line Contactor ahead of the soft start required as referred to in the ATS22 users manual?

Accepted Answer

Issue:Is a Line contactor required ahead of the soft start?Product Line:Altistart 22, ATS22Environment:All models and serial numbersCause:NoneResolution:The purpose of the line contactor is to provide a means of removing AC line voltage from the softstart. Due to leakage currents through the solid state switches, hazardous voltages can be present on the load side of the softstarter when power is applied to the line side of the softstarter. Also, the line contactor can be controlled to open if the ATS22 faults. Some faults are the result of SCRs shorting. If multiple SCRs fail in a shorted condition, full voltage power passes through and will either single phase or continue to run the motor. The KM1 would interrupt the power circuit.A line or isolation contactor such as KM1 shown in wiring diagrams, located in the Annex of the ATS22 Users Manual (BBV51330) is strongly suggested but not required.

Question 4

Is the use of Noalox antioxidant, for termination to Panelboards, prohibited?

Accepted Answer

Issue:Can a Noalox antioxidant, for termination to Panelboards, prohibited?Product Line:NQ/ NF/ I Line/ QMBEnvironment:InstallationCause:RestrictionsResolution:The use of an antioxidant , such as Noalox, on Panelboard Main Lugs is not required.The lugs are UL listed for use with copper or aluminum conductors without the use of ANY anti-oxidation supplement. The use of an antioxidant is not prohibited, but assurances must be made that the brand used, is a NON PETROLEUM based product. If a petroleum based product is used and comes in contact with the insulating base, the insulating base material can be degraded.

Question 5

Can the branch neutral bars be cut or disconnected in a QO or Homeline load center to form one neutral on one side and one ground bar on the other side?

Accepted Answer

Issue:ApplicationProduct Line:QO and Homeline Load CenterResolution:No, The neutral system in the QO and Homeline load centers are considered a split branch neutral system. Half of the branch neutrals are on the left and half on the right, with both branch neutral bars connected to the main neutral bar at the top of the interior. So it is not acceptable to modify the neutral bar from the way it was designed, tested, and manufactured. The neutral bar was not designed to have the left side separated from the right side. Whether or not the neutral bar can be used to terminate equipment ground wires is dependent upon the application of the load center. The neutral bar is rated to accept neutral conductors and ground conductor (in unused neutral spaces) ONLY if the load center is used as service entrance equipment. If the load center is NOT a service entrance load center (installed as a subpanel downstream from the service entrance equipment), then a separate ground bar needs to be purchased and installed for ALL ground conductors. Do NOT cut or separate the existing neutral bar to form a separate neutral and ground bar. This modification is not allowed per UL procedures and would VOID the UL listing and warranty.

Question 6

What is the difference between XB4/XB5 and ZB4/ZB5?

Accepted Answer

Issue: How are complete devices and parts indicated in the 22mm lines? Product Line: Push Buttons and Operator Interface Environment: Harmony Pushbuttons Cause: Product Features Resolution: XB indicates a complete device and ZB is components.While the 4 indicates the metallic line, and the 5 indicates the plastic line. An XB4 part number will be a complete metallic 22 mm operator. A ZB4 part number is a metallic component. An XB5 part number will be a complete plastic 22 mm operator. A ZB5 part number is a plastic component.

Question 7

Does the branch wiring of a hospital isolated power system require color coding?

Accepted Answer

Issue:Color coding required for the branch wiring of a hospital isolated power systemProduct Line:Hospital isolated power systemsEnvironment:NFPA99, NEC517.160Resolution:The NEC requires color coding of the conductors based on the NEC edition in effect as referenced below: NFPA 70 (2011 & 2008)517.160 Isolated Power Systems (A) Installations. (5) Conductor Identification.The isolated circuit conductors shall be identified as follows:(1)Isolated Conductor No. 1 — Orange with at least one distinctive colored stripe other than white, green, or gray along the entire length of the conductor(2)Isolated Conductor No. 2 — Brown with at least one distinctive colored stripe other than white, green, or gray along the entire length of the conductorNFPA 70 (2005)517.160 Isolated Power Systems (A) Installations. (5) Conductor Identification.The isolated circuit conductors shall be identified as follows:(1)Isolated Conductor No. 1 — Orange(2)Isolated Conductor No. 2 — Brown

Question 8

What is a ZB2BE102C?

Accepted Answer

Issue: What does the C indicate in ZB2BE102C?Product Line: Push Buttons and Operator InterfaceEnvironment: 22mm ZB2Cause: Clarify the difference between ZB2BE102C and ZB2BE102 Resolution:ZB2BE102C is labeled to be sold in the Asian market only. That is what the C indicates. ZB2BE102 is the same unit and is available in the US.

Question 9

What is DPF ?

Accepted Answer

Displacement Power FactorDisplacement Power Factor is caused by a reactive component in the load.

Question 10

What does the term "NEMA Type 1A" refer to?

Accepted Answer

NEMA Standards Publication 250-1997, "Enclosures for Electrical Equipment (1000 Volts Maximum)" no longer lists this enclosure type. This enclosure type is commonly accepted to be referring to a NEMA 1 enclosure with a gasketed cover.

Question 11

What is the Nomenclature for Common Relays

Accepted Answer

Issue:User wants to know the abbreviations for common relay types. Resolution: Normally Open (NO) contacts connect the circuit when the relay is activated; the circuit is disconnected when inactive. This type is also called Form A or a make contact.Normally Closed (NC) contacts disconnect the circuit when the relay is activated; the circuit is connected when inactive. This type is also called Form B or a break contact.Change-over (Double-Throw) contacts control two circuits: one NO and one NC contact with a common terminal. This type is called Form C or a transfer contact. It is often “break-before-make.” The opposite, “make-before-break,” is Form D. Other common relay types: SPST (Single Pole Single Throw): Two terminals that can be connected or disconnected. With coil terminals, there are four total. Contact can be NO or NC; abbreviations SPNO and SPNC clarify this.SPDT (Single Pole Double Throw): One common terminal connects to either of two others. With coil terminals, there are five total.DPST (Double Pole Single Throw): Two pairs of terminals, equivalent to two SPST relays operated by one coil. Six terminals total.DPDT (Double Pole Double Throw): Two rows of change-over terminals, equivalent to two SPDT relays operated by one coil. Eight terminals total.4PDT (Four Pole Double Throw)/Quadruple Pole Double Throw (QTDP) : Four rows of change-over terminals, equivalent to four SPDT relays or two DPDT relays operated by one coil. Fourteen terminals total.

Question 12

Insulation Resistance Testing and Humidity

Accepted Answer

Issue:How does humidity affect insulation resistance testing results?Product Line:Circuit BreakersEnvironment:Molded case and insulated case breakersResolution:High humidity can drastically reduce insulation resistance testing results for circuit breakers.Some equipment acceptance testing documents suggest values above 100 mega ohms and normally that is okay however high humidity can drastically reduce the results of the insulation resistance values. Below is a sample of how higher humidity can reduce the IR values, making the 100 mega ohms acceptance testing values invalid.40% humidity: breaker IR value above 500 mega ohms, typical 1 G ohm*75% humidity: breaker IR value around 10 mega ohms*95% humidity: breaker IR value around 4 mega ohms**All values above are functional and conforming. Values derived from test data on Powerpact H frame breakers in a Schneider Electric laboratory.The IEC 60947 standard, section 6.1.3.1 states that IR testing should be done below 50% humidity and states a 1 M ohm minimum IR value for a new breaker.NEMA AB-4 recommends IR values for breakers, less than one mega ohm (1,000,000 ohm) should be investigated. The Schneider Electric field testing and maintenance guide also states the same one mega ohm value, as written below.Severe environmental conditions can reduce the dielectric strength ofmolded case circuit breakers. Check insulation resistance during electricalsystem testing.To check the insulation resistance, perform the following steps:1. De-energize and isolate the circuit breaker.2. Clean the circuit breaker as described earlier.3. Using a megohmmeter with a capacity of 500–1000 Vdc, apply voltagefrom:a. Each phase-to-ground with the circuit breaker on (circuit breakercontacts closed).b. Phase-to-phase with the circuit breaker on (circuit breaker contactsclosed).c. Between each line and load terminal with the circuit breaker off(circuit breaker contacts open).4. Record resistance values. Resistance values of less than one mega ohm(1,000,000 ohm) should be investigated.

Question 13

What is the difference between PNP and NPN when describing 3 wire connection of a sensor?

Accepted Answer

Most industrial proximity sensors (inductive, capacitive, ultrasonic and photo electric) are solid state.The term solid state refers to the type of components used within the sensor. Solid state electronic components such as transistors are used to switch the output of the sensor upon detection of an object.Two specific types of 3 wire sensors are available; PNP and NPN. The difference is a result of the internal circuit design and type of transistors used. Refer to attached document for simple explanation of the two.A key point to observe is that PNP and NPN has nothing to do with whether the sensor is normally open (N/O) or normally closed (N/C), i.e. a PNP sensor may be either N/O or N/C as can an NPN be either N/O or N/C.Please note that the subject of this FAQ is specifically related to wiring PNP/NPN outputs for sensors, not to give a detailed understanding of transistor technology. However, for ease of understanding please see attached a page extracted from our Practical Aspects book, showing (in brief) transistor terminology and circuit diagrams. Further learning material regarding PNP and NPN transistors can be found online from several sources. Why two types?The selection of a PNP sensor verses an NPN sensor is determined by the nature of the circuit the device is to be used in. When used in a traditional relay type control circuit, it is normally possible to use either the PNP or the NPN type of sensor as shown below. PNP sensors tend to be more commonly used. WiringTraditional relay type control circuit; Use with a programmable logic controller (PLC).When selecting a sensor to be used with a PLC, it is very important that the sensor matches the type of PLC input card to be used.Two types of input cards exist, those that 'sink' current (also known as positive logic) and those that 'source' current (also known as negative logic). It is worth mentioning, that whilst the terms sinking / sourcing and positive / negative logic are well known in some industries, they are not always commonly used terms. It is therefore important to identify the type of sensor to be used with the PLC card based on the PLC manufacturer's documentation and / or wiring diagrams.Most common in Europe is the 'sinking' type of input, these will be used with the PNP sensor as shown below. Less common nowadays are input cards that 'source', these were popular in Asia and require the NPN type of sensor in order to operate correctly. Many modern PLC input cards can be configured and wired to be either 'sinking' or 'sourcing' although it will usually necessitate all inputs on a particular input card being configured the same. NOTE the dotted line in the following diagram is optional and may or may not be required, depending on your hardware/setup. The key wires to take note of are solid red, black and blue wires.

Question 14

Who is my local distributor?

Accepted Answer

IssueWho is my local distributor?ResolutionFor United States distributors:https://www.se.com/us/en/locate/257-us-distributor-locator/where-to-buyFor distributors in Canada:http://www.schneider-electric.ca/sites/canada/en/support/partners-locator/partners-locator.pageFor distributors in Mexico;https://www.se.com/mx/es/locate/356-red-de-distribuidores/where-to-buy

Question 15

Where can I apply for a job with Schneider Electric?

Accepted Answer

Resolution:For career opportunities and questions please visit our dedicated site Careers: Work at Schneider | Schneider Electric USA (se.com)

Question 16

How do I become a supplier for Schneider Electric?

Accepted Answer

Issue: How to become a supplier for Schneider Electric Product Line: Source Materials Environment:Products sold and used in the United StatesResolution:For information and help on becoming a supplier for Schneider Electric please refer to the supplier resource center linked below: http://www.schneider-electric.us/en/about-us/supplier-resource-center/

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