Here's the scenario; you are feeling contented after spending an entire hour vacuuming your entire carpeted floor with your wet/dry industrial vacuum cleaner. As you lean over to pack it away, you get a shock as your hand accidentally brushed against the stainless steel drum. This actually happened to a customer who called in with regards to his Karcher NT38/1 ME Classic.

So why does this happen?

The shock the customer got was actually from static electricity generated from the friction between dust particles and the stainless steel drum. Since the NT38/1 is double-insulated like all good power tools, there's no risk of electrocution. With the same token, there is also no way for built-up of static electricity to travel to ground.

How can I avoid getting a nasty shock?

The basic idea is to stop the dust particles rubbing against the steel drum. A quick fix is to use the optional dust bag for the NT38/1. Unfortunately at RM110 for 10 pieces, it's understandable that after having spent on a bagless wet/dry vacuum cleaner, the last thing you want is to buy consumable dust bags.

The other two options is to either ground the tank by touching the drum to a grounded bare metal from time to time during vacuuming, or by adding or vacuuming some water into the steel drum before vacuuming your carpets!

The moisture inside the drum should in theory prevent the air and dust particles inside the steel drum from drying out. Damp dirt means no friction, which also means no chance of static electricity build up. The only downside to this method is that it does get quite messy and you would also have to rinse out the drum after each use.