A handy extension cable of 40ft (12.2m). Together with the standard grounding cable of 16.5ft (5m), the reach becomes 17m. You can connect more extension cables if you wish, for an even larger span, without loss of grounding effect.
You can use this extension cable if you use the adapter in a wall socket or with the grounding rod.
Total reach with the 5m (standard cable) becomes 5m + 12.2m= 17.2m.
To connect 2 grounding items to this extension cord you'll need a splitter. For 3 grounding items, 2 splitters, etc...
You can use as many interconnected extension cables as necessary without loss of grounding effect.
Note: You can also use your own grounded extension cord to plug in the adapters, in order to get to a grounded outlet. The advantage of this grounding extension cable is also the finer cable that can possibly go under the door.
For extra peace of mind and super safe use, the included cable has a built-in 100 kOhm resistor.