Testing gives a 'big' spark

[Red_MAv]

I have a fuse box mounted on the firewall of my QG where there is a positive wire in from the dual battery and it disperses through about 6 glass fuses to various accessories. When I connect my basic tester to the earth of the dual battery and touch the other end on the far end of a fuse it lights up the globe in the tr=ester as it should but it gives massive spark at the contact point. I dont recall this being normal. It used to just light up so i could see if the fue was still intact. Any ideas on what would cause this. The car doesnt get used much and i had just recharged it the night before.

[GeeC]

What is the voltage and wattage of the light in your 'tester'?

[Red_MAv]

Ive no idea, its just a metalic silver tester about the size of a pen i've had it for 20 years or so, but i have never had it spark like it does now, I thought maybe something wrong with the electrics but is it likely to be the tester maybe?

[Dooley]

Seems a bit strange... is the circuit you were testing okay ? Has it been shorting or anything, was the fuse you were trying to test good or not ?

Does it happen with every fuse ?

Maybe try a multimeter, different test light, led with leads etc. and play around to try and find the issue. Try earthing off the chassis instead... ?