Originally Posted by
Billy Merrill
Its time to get the subpanel installed.
Your dryer and your tools are wired differently.
The dryer receptacle has 3 wires, 2-120vac hots and a neutral, but no ground.
A dryer uses both 120vac and 240vac power. The 120vac return path is the neutral and for 240vac the return path is the opposing hot.
Anytime the dryer is plugged in the neutral is energized.
Your 240vac tools also use 3 wires, the 2-120vac hots just like the dryer, but require a ground. They do not use a neutral like the dryer. When you use the dryer receptacle to power your tools you are using the neutral as a ground. It is against NEC to use a neutral wire as a ground. When you power your tools from the dryer outlet you are doing this. But it works because the neutral bus bar and the ground bus bar are connected at the main panel.
If you use a splitter and the dryer is plugged in then you will be connecting the ground of the tools to a current carrying conductor of the dryer. This creates a shock hazard to the user of the tools. Even though the neutral and the ground are connected together at the main panel ,electricity will always take the path of least resistance which can be the operator of the tool.