How do I properly hook up a step down transformer?

Question

I need to drop 220VAC from Europe to 110VAC to use with electronics from the US. I used a step down transformer and have 110VAC coming out. A surge protector is following but when I put an outlet tester it indicates 'open ground'. I measured from the hot to ground and got 78VAC and from the neutral to ground and got 30VAC. Is this normal and safe to plug in electronics into the power strip? I had to replace a computer power supply and a UPS battery already. Do I have to ground the neutral from the transformer output to ground?

Answer 1

Is the step down transformer also an isolation transformer? Was it prewired or did you wire it yourself?

Where is the ground on the secondary outlet box tied to? It has to connect to the ground on the primary side, and also to the ground of the transformer case.

From your readings, it appears you have the secondary totally floating. I think you need to tie the neutral from the secondary to the neutral from the primary.