relay basics

[njkmonty]

is ok to have a relay  turn on other multiple relays?  if so  is there a rule about switching the ground or vc  are there other unknown issues that a novice may be aware off?

[Zero999]

It makes no difference which side of the coil is switched. A reverse parallel diode should be used to protect the switching transistor.

The question is too vague to give any more information than that.

[njkmonty]

is it ok to use a 5v spdt relay to switch on  for example 5  x 5v dpdt relays? 

ive got one of these working (see below  how ever i thought it would be easier to use the spdt relay to be able to switch on a seperate dpdt relay which i have plenty laying around.
when i bought the relay module i thought it was dpdt

[Zero999]

is it ok to use a 5v spdt relay to switch on  for example 5  x 5v dpdt relays? 

ive got one of these working (see below  how ever i thought it would be easier to use the spdt relay to be able to switch on a seperate dpdt relay which i have plenty laying around.
when i bought the relay module i thought it was dpdt

It would work, but isn't good design practise, which would be to but the correct DPDT module and keep that one for another project.

I hope those relays aren't switching mains. It's unlikely those boards have sufficient creepage distances.

[tpowell1830]

is ok to have a relay  turn on other multiple relays?  if so  is there a rule about switching the ground or vc  are there other unknown issues that a novice may be aware off?

Some relays have a built in diode and are polarized, check your relay diagram, usually on the relay box, to see if there is a diode shown.

As for switching in the way that you describe, it depends on your application/use. If this is a one-off hobby project, I see no problem doing this. If this is an industrial application, I suggest checking with your local electrical authority/engineer for specifics. I have worked for companies as an electrician where the only requirements was results, and as long as there was no danger to humans or equipment, anything that would get the job done was allowed. However, some industrial environments, and I have worked these as well, have rules and guidelines in place.

Hope this helps...