Pass through current is in my opinion not a rating that should be taken into account for normal operation of the inverter .Originally Posted by Sparks
CB should be rated at the load that is intended to used under normal conditions and the wire size would follow.
What we are seeing is guys installing 5kw inverters along with a 5KWH battery and then all protection is based on the pass through current of a 10kw system.As soon as there is a dip in power/loss of power/loadshedding the inverter and battery are trying to pick up the pass through current and you end up with a low DC voltage fault which indicates that the actual inverter was overloaded
We are also seeing all socket outlets and light circuits in a domestic dwelling running off the inverter and the kitchen has a dishwasher , wash machine, kettle , dishwasher etc and the worst is when they include the geyser and stove.
Owners are then told to make sure that they don't use to many appliances at the same time which in my opinion contravenes Clause 7.12.2.4
The battery warranty is gone because the warranty terms state that on average the battery should only discharge at 0.5c even though spec says 1c and more than 3 overloads voids warranty
An inverter is a generator not an appliance - We would never load a generator at 100% load and expect it to last .
Then we also have clause 5.5.2 and 5.3.1 with reference to Annex c which stipulates sizing of power requirements for socket outlets
SANS 10142-1 ed3.1
7.12.2.4 Where the alternative supply is intended to provide a supply to an
installation that is not connected to the main supply, or to provide a supply as
a switched alternative to the main supply, the capacity and operating
characteristics of the alternative supply shall be such that danger or damage
to equipment does not arise after the connection or disconnection of any
intended load as a result of the deviation of the voltage or frequency from the
standard range. Means shall be provided to automatically disconnect such
parts of the installation, as may be necessary if the capacity of the alternative
supply is exceeded
5.5.2 Harmful effects by electrical equipment
Electrical equipment shall be so designed and arranged that any damage as
a result of a fault be localized as much as possible. The equipment shall not
have harmful effects on other equipment or on the power supply during normal
service (including switching operations). Factors that can lead to harmful
effects include
a) the power factor,
b) inrush current,
c) asymmetrical load, and
d) harmonics
5.3.1 Estimated load
The load of an installation shall be estimated to determine the type and
capacity of the required electricity supply.
NOTE 1 Annex C gives an example of estimating the load for residential installations
but the method is not to be regarded as an exact method.
NOTE 2 The supplier may have special requirements for large installations and for
installations that need special consideration.
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