CARBONE Digi-Tig250ACDC, Operator'S Manual

A-4                          INSTALLATION                                      A-4 

MACHINE GROUNDING AND HIGH 
FREQUENCY INTERFERENCE 
PROTECTION  

This welder must be grounded! See your local and 
national electrical codes for proper grounding 
methods.  
  The high frequency generator, being similar to a 
radio transmitter, may cause radio, TV and 
electronic equipment interference problems. These 
problems may be the result of radiated interference. 
Proper grounding methods can reduce or eliminate 
radiated interference.   
Radiated interference can develop in the following 
four ways:   
1    Direct interference radiated from the welder.   
2    Direct interference radiated from the welding 
leads.  
3 Direct interference radiated from feedback into the 
power lines.   
4 Interference from re-radiation of "pickup" by 
ungrounded metallic objects.   
Keeping these contributing factors in mind, installing 
equipment per the following instructions should 
minimize problems.   
1 Keep the welder power supply lines as short as 
possible and enclose as much of them as possible 
in rigid metallic conduit or equivalent shielding for a 
distance of 50 feet (15.2m). There should be good 
electrical contact between this conduit and the 
welder case ground. Both ends of the conduit 
should be connected to a driven ground and the 
entire length should be continuous.   
2 Keep the work and electrode leads as short as 
possible and as close together as possible. Lengths 
should not exceed 25 ft (7.6m). Tape the leads 
together when practical.   
3 Be sure the torch and work cable rubber 
coverings are free of cuts and cracks that allow high 
frequency leakage.   
4 Keep the torch in good repair and all connections 
tight to reduce high frequency leakage.   
5 The work piece must be connected to an earth 
ground close to the work clamp, using one of the 

following methods:   
a) A metal underground water pipe in direct contact 
with the earth for ten feet or more.   
b) A 3/4" (19mm) galvanized pipe or a 5/8" 
(16mm)solid galvanized iron, steel or copper rod 
driven at least eight feet into the ground.   
The ground should be securely made and the 
grounding cable should be as short as possible 
using cable of the same size as the work cable, or 
larger. Grounding to the building frame electrical 
conduit or along pipe system can result in 
reradiation, effectively making these members 
radiating antennas.   
6    Keep cover and all screws securely in place.   
7 Electrical conductors within 50 ft (15.2m) of the 
welder should be enclosed in grounded rigid 
metallic conduit or equivalent shielding, wherever 
possible. Flexible metallic conduit is generally not 
suitable.  
8 When the welder is enclosed in a metal building, 
the metal building should be connected to several 
good earth driven electrical grounds (as in 5 (b) 
above) around the periphery of the building.   
Failure to observe these recommended installation 
procedures can cause radio or TV and electronic 
equipment interference problems and result in 
unsatisfactory welding performance resulting from 
lost high frequency power.   

INPUT CONNECTIONS   

Be sure the voltage, phase, and frequency of the 
input power is as specified on the rating plate, 
located on the rear of the machine.   
Have a qualified electrician provide input power 
supply to the receptacle or cord in accordance with 
all local and national electrical codes. Use a single 
phase line or one phase of a two or three phase 
line. 

Choose an input and grounding wire size according 
to local or national codes. Refer to 

 the Technical 

Specifications 

page at the beginning of this section. 

Fuse the input circuit with the recommended super 
lag fuses or delay type circuit breakers.