An old house built pre-50s has cloth-wrap wiring. I cannot find the amps or maker anyplace on any panel or breaker. There are five panels in the house: one main and 4 sub. There is also a low volt system. Is any of this still up to code and where can I find info on this type system?
It's called Grandfathered
If you build something, and it's up to code at the time, and they update Code, you usually don't need to tear out the work and retrofit.
There are exceptions, e.g. for earthquake codes for high-value/traffic buildings, or ADA when you're doing a major renovation anyway.) Wiring isn't one of them.
It's really about quality of work
If the original system was properly wired, it is a great deal safer than newer work that is wired wrong.
So you need to go through the system, with an eye for how it should have been built at the time. This isn't far off of today, except for the addition of grounds.
You can retrofit additional safety
In 2014 (really!) they amended Code to allow you to retrofit grounds at will. The ground path does not need to follow the other wires, it just needs to be large enough for the load.
If you want to protect against failing electrical wires sparking and arcing and starting fires, you can fit arc-fault circuit interruptor (AFCI) circuit breakers.
If you want to protect house users from electrocution (e.g. hair dryer dropped in bathtub), you can install ground-fault circuit interruptor (GFCI) devices. These are commonly available as
- a circuit breaker
- a "blank-face" device you put inline in the wiring
- a "live-face" device, same as a blank-face except they give you a couple of convenience outlets
They make dual-mode AFCI and GFCI breakers. It's cheaper to use an AFCI breaker and a GFCI blank-face or live-face though.
The four sub-panels are very good news. That means if a subpanel is dangerous (FPE), obsolete (Pushmatic), cheap (Homeline), weird (Q-line), or just expensive to get GFCI/AFCI breakers for (QO/CH) -- you can swap the subpanel easily enough, without any serious danger.
Let's start with the easy part first. The insulation wiring you are talking about is known as RH or RHW, which was common during pre 50's construction. It is a rubber insulation and is subject to aging and crumbling particularly when it has overheated. Like in boxes connected to ceiling fixtures, use extreme caution handling it.
Now if you have 4 subplanes, the original edison base fuse panel was probably upgraded. Then the need to increase the service size, and additional breakers caused the additional panels. That may mean that your electrical system may have been upgraded during the additions. So you may not have the type RH/RHW insulation throughout the house.
If practical, you should consider replacing this wiring for two main reasons. First pre 50 houses were ungrounded systems (no ground wire). Second the normal life of an electrical system is 60 Years. This was developed by testing systems and they found the first 30 years of an installed system, there should be minimal failure. Then over the next thirty years there will be 50% failure of the system. So after 60 years, maintenance of that system becomes impractical compared to replacement of a new system. Keep in mind this is not for one system it is simply an overall study of multiple systems.
So you might want to get with a reputable electrical contractor and survey what can be done to upgrade your system.
Hope this helps