Shunt (electrical) called a "crowbar" as it is likened to dropping an actual crowbar across a set of bus bars (exposed electrical conductors). An ammeter shunt allows the measurement of current values too large to be directly measured by a particular ammeter. In this case the shunt, a manganin resistor of accurately known resistance, is placed in parallel with the moving coil galvanometer, thus all of the current to be measured will flow through it. In order not to disrupt the circuit, the resistance of the shunt is normally very low. The voltage drop across the shunt is proportional to the current
Electrical contractor Electrical contractor An electrical contractor is a business person or firm that performs specialized construction work related to the design, installation, and maintenance of electrical systems. An electrical contractor is different from an electrician; an electrician is an individual tradesman and an electrical contractor is a business person or company that employs electricians. Both usually hold licenses and insurances to properly and safely operate a business, protecting the employees and home owners/business owners from insurance liabilities. These requirements vary from state to state. Electricians may work for an electrical contractor, or directly for individuals or companies. Electrical contractors are generally